By Richard Lunsford
After appropriate housing, temperature and diet, filtration is the next prime
concern in an aquatic or semi-aquatic turtle’s long-term well-being. The same
basic water chemistry concerns apply to turtles as fish, but turtles require
stronger filtration. I’ll break down filtration per this outline:
Filtration Capacity Principles for Turtles.
Filter Media – what it is, what it does.
Overview of Popular Filter Models & Strategies.
What is a Wet/Dry
Can I get rid of Nitrate without Water Changes?
Water Changes – Why
What Test Kits
do I need?
Where To Buy.
I.) What is Aquarium Filtration?
It’s a 3-part System:
– removal of particulate matter from the water (i.e.: crud, turds, uneaten food,
etc). This matter builds up on the mechanical filter media (sponge, filter
floss, etc) and is removed from the tank when you remove the mechanical filter
media from the tank & clean or replace it. This is the type of filtration most
people are familiar with, since it makes the water LOOK clean. It ranks second
in importance. Note: mechanical filtration is easier if you don’t have gravel in
your tank (the bare-bottom tank approach).
– the use of chemical media in the filter to remove unwanted dissolved
substances from the water. The most common example is activated carbon. Some
organic compounds bind to activated carbon (this is called adsorption, not
absorption, since they don’t enter the carbon) – this can make the water look
‘sharper’ and reduce unpleasant smells, but it’s a luxury. Activated carbon can
remove some medications and tannins (coloring agents released into water if you
use peat in the tank). Another example is ammonia remover, which removes ammonia
from the tank (until the media’s full & must be replaced) but can interfere with
biological cycling. The common thread across chemical filtration is it uses
media that are fairly expensive, have to be replaced fairly often, & most
chemical filtration is unnecessary although it can be a luxury. Ranks 3’rd in
- #1 Important filtration system in your tank, & the one more people are
ignorant of. Aquatic turtles (and fish, snails, etc) produce nitrogenous wastes
in their bodies, and excrete part of it as ammonia, which builds up rapidly & is
very toxic. Beneficial bacterial colonies (Nitrosomonas) grow on your
filter’s biological media (Biowheel, BioMax ceramic rings, Aquaclear sponge,
etc) that break this ammonia down into nitrite. Nitrite is also quite toxic. A
second type of bacteria (Nitrobacter) grows on the media that converts
Nitrite into Nitrate, which is only toxic at high levels. Nitrate is part of
what you dilute when you do water changes in your aquarium. Biological
filtration & the need to keep your bacteria alive is why your filter must run
24/7, and why during the first 4-6 weeks (while the bacterial colonies slowly
develop) you must change your tank water at least once per week!!!
Some try to jumpstart bacterial colonization with store products like Cycle; you
may get mixed results. By all means try it, but test for ammonia & nitrite to
see if it ‘took. For tips on jump starting cycling, keep reading!
Bottom line: Biological filtration capacity is your number one
concern (due to the nitrogen cycle). Mechanical is useful. Chemical is a luxury,
although activated carbon is a great last resort of ‘swamp smell’ proves a
Capacity Principles for Turtles.
capacity for anything is an inexact science. Your need depends on tank size, how
many turtles and tank mates are in it, how much and what you feed, and whether
you feed in the tank or a separate container, etc… Many people feed their
turtles in a separate container (like a Rubbermaid tub); not only does this cut
down on rotting food scraps and juices in the tank, but turtles often poop
shortly after eating, and will do so in the tub. Some feed in a separate
container, some don’t – see what works for you.
My rule of thumb is
filtration rated for a tank 2 - 3 times the size of what the turtles are in.
factor in only having the tank partially filled; a half-filled 20 gallon tank
should get a filter rated for a 60 gallon tank, not a 30 gallon. This assumes a
‘turtle load’ of about 3 turtles up to a year old in a 20 gallon long, perhaps 3
adult male basking turtles in a 75 gallon tank, etc… If you have a 75 gallon
tank with one basking turtle, a filter rated for a 75 gallon tank might do
although I’d still aim for twice. Factor in tank mates; fish enthusiasts
recommend an adult Oscar should have a 55 gallon tank
and 2 Oscars should have a 75 gallon tank alone. Adult goldfish have a 20-30
gallon/apiece need. Smaller tank mates don’t require so much, but they DO
it takes 4-6 weeks to build up bacterial colonies, so make sure
you do a large water change AT LEAST weekly until your tank cycles. You will see
for sale products like Cycle that purport to dump reams of beneficial bacteria
into your tank. Feel free to try, but I've heard mixed reports so don't assume
it worked without testing ammonia & nitrite days afterward.
A great technique to speed cycling is to 'seed' your
new filter with biomedia from an old one. If you have a Fluval 304 on
an old tank, and you're putting a Fluval 404 on a new tank, put some Bio-Max
ceramic rings from the 304 in a media chamber of the 404.
THAT will jumpstart things a lot. Better yet, put an established
filter from another tank on the new tank.
On large tanks (55 gallon
& up) consider using 2 filters; this spreads
out the intake and outflow a bit, and if one filter breaks, you don’t loose all
your bacterial colonies.
Put intake and outflow
lines at opposite ends of the tank; this helps ensure your filter filters all
the water, without ‘dead pockets.’
Turtles are more resistant to bad
water than fish. That's why quite a few turtle keepers don't know much about
cycling; they never had all their turtles floating belly up from ammonia like
fish keepers do. Some turtles are unusually sensitive to poor water quality
(i.e.: map turtle, soft-shell turtles & the exotic Fly River Turtle). And I have
read about high ammonia levels irritating turtles’ eyes. Remember: the smell of
ammonia is used as an irritant to rouse unconscious people. That should tell you
something about how it feels on mucous membranes!
III.) Filter Media
– what it is, what it does.
- depends on filter & purpose. Different brands of filter may use different
media for the same purpose (for example, for biological filtration, Aquaclear
filters use a sponge, Fluvals use porous hollow ceramic cylinders called Bio-Max
and Magnum filters use Biowheels). Some media types can perform 2 filtration
functions (Aquaclear sponges mechanically and biologically filter).
Media examples by filter type:
BioMax. Or you can go to
Pet Warehouse and look at some biomedia
Deluxe - you'll
have to use with a UGF; otherwise no biofiltration.
Magnum 350 Pro
- Biowheel Pro 60 comes with. You can put biomedia in the media basket
for more power, but the media basket wasn’t meant for that.
- sponge. Comes with 1; add a second on top of that.
Ehfisubstrat, a sintered glass product, or
Ehfilav, porous volcanic rock. You could try substituting BioMax or
something and see what mileage you get.
- plastic Bioballs.
- fairly expensive and a luxury. You don't need it but may want it. Basically,
some organic compounds stick to it; that's called Adsorption (not ab,
ad...there's a difference). It can remove some medications from the tank when
you're done treating, may cut down on odors, and some think it makes the water
more 'sparkling' looking. It doesn't have the surface area for bacteria of
BioMax, but some bacteria grow on it. Needs to be changed at least monthly, or
it's just inefficient biomedia. Marineland is a reputable brand.
Dubious value. They bind up ammonia, which is great in the here and now, but
since that ammonia doesn't get to your biomedia these can (in theory) interfere
with normal cycling! Sooner or later you may not keep up with media changes, and
they do exhaust their binding capacity.
When you just want it to look
clean (Mom's visiting, etc...). Filter floss is popular. Magnum 350 canisters
include a micron cartridge that 'polishes' the water. Mechanical filtration is
important in any filter to stop particulate crud before it gums up the surface
area in your biological media. In the Aquaclear, the sponge does double duty -
biological and mechanical.
using peat to lower pH and
hardness, phosphate removers, etc...don't worry about this right now. And maybe
Overview of Popular Filter Models & Strategies.
Which filter is best is hotly
debated and a book in it's own right. There are too many brands & models to
review all of them. Based on my knowledge & the market as of 1-13-05, here's my
take on the summaries I've read of the most popular brands for turtles:
Marineland ‘Canister’ Filters - Magnum
350 Deluxe &
350 Pro (don’t get the most basic system) & Magnum
H.O.T. Pro: Only the Pro versions have biowheels (2). Biowheels splash
too much, unless you have a nearly full tank or provide something for the water
to run down. Only get a Magnum 350 Deluxe if you're going to hook it to an UGF,
since with no biowheel there’s no biological filtration. That arrangement works
well. The output is designed to spray across the upper water in a filled tank,
so you’ll need to stop the spray/water fall effect in partially filled tank (a
piece of plastic tubing jammed over the output may work fine). Get the Deluxe or
Pro; the basic version of the 350 now includes the media basket but
lacks the Double Quick-Disconnect Valves.
H.O.T. is similar to the 350 Deluxe, and the
H.O.T. Pro to the 350 Pro (but only one biowheel); the H.O.T.s have a
lower flow rate, are less powerful, somewhat cheaper & are canister filters that
hang on back of the tank. H.O.T.s don’t seem to lose their prime easily, but
wouldn’t be ideal for tanks with a lot of height above the water. Note:
The biowheels on the 350 Pro, H.O.T. Pro & Emperor 400 are not interchangeable!
You can put biomedia in the media basket for some biofiltration, but it
doesn’t hold a lot.
Power Filters – The stereotypical ‘hang on back of the tank’ aquarium
filter. Tend to offer great power very cheaply, but if the tank's not full and
the power goes out, it could lose its siphon and burn up when the power comes
back on. Not recommended in partially filled tanks. Most power filters output
water in some sort of water fall of splash that’s annoying in partially filled
tanks. Hagan’s Aquaclear is the leading example, and the
Aquaclear 500's are cool, if you silicone a sheet of plexiglass to the
hood lip to stop the water fall effect. I don’t find turtles in noisy water in
nature, and I don’t like waterfalls in my tanks. One of the 500’s key
competitors is Marineland’s
Emperor 400 - Pretty good in full tanks, but has a pair of biowheels and
we've already been over the splash thing. You CAN add additional
biological filtration capacity by using
Cell-Pore Biocartridges (on clearance so act fast!). In my experience, the
Emperor 400 is much less effective than the Aquaclear 500 at coping with low
water levels (flow rate drops a lot when the water level is quite low). I
only recommend the 400 for tanks that are almost full.
Internal Filters - Some love
Fluval 4 internal filters; often I see posts about using 2. I get the
impression they aren't as powerful as the external 404 canisters, hold less
media and take up tank space. I pass, but some like these. The
Duetto 50 & 100 are often hawked for turtle tanks, but widely regarded
as inadequate for the purpose. Cute, but I recommend you avoid Duettos, except
in small, shallow-water setups like 20 gallon long tanks with under 4” water
with young mud turtles). More recently the
Whisper line of upright internal canisters (10i, 20i & 30i) for tanks with
2” water & up have become popular, although they produce a water fall like a
power filter (this can be dealth with creatively).
Low-End Canister Filters
– represented by the
ZooMed 501 Turtle Canister & the Fluval 104 & 204 and FilStar XP1 & XP2. On
the Turtle Forum, the 501 has gained considerable attention while the others
mentioned aren’t posted about often. The 501 is made to sit at tank level; the
motor allegedly isn’t powerful enough to merit keeping it under the tank (say,
in a cabinet like larger external canister filters). Here’s
a nice 501 review Mahler found at Aquarium Life Support Systems. It has a
sponge for mechanical filtration, porous ceramic ‘noodles’ for biofiltration & a
chamber for activated carbon (which you can replace with more biomedia if
desired). Output is via a spray bar. It can allegedly run dry for 30 days (I
don’t recommend testing that out…). Another forum member, Charles, reported the
501 can handle fairly shallow water tanks (at least down to 4-5” if the tank
wall’s not too tall; Charles said the intake reaches the bottom of a 12” tank),
primes easily & doesn’t require re-priming after a blackout. Rated for tanks up
to 30 gallons. However, we’ve had enough members post about reliability problems
over time that I don’t personally recommend this filter (caveat: I’ve never
Mid-Range Canister Filters
– A tall canister sits below the tank; it’s hollow & can hold a lot of media, &
being below the tank won’t lose its prime during blackouts. Hagan’s
Fluval 404 - quite popular with
turtle keepers. Available for ~$115. Advertised as rated for up to 100 gallon
tanks. Includes all needed media. Some fish forum regulars think it's likely
cheaper made, less reliable and won't last as long as Eheim canister filters
like the Pro II series. If you get a 404, some recommend you fill the canister
with water after servicing; I don't think the manual tells you that, and you may
need to know. The 404 has a reputation for difficult priming (getting the flow
of water started so it can work) in partially-filled tanks; some people hate it,
and some aren’t affected. The output is designed to agitate the water surface,
so in partially filled tanks you’ll need to put tubing or hose over the output &
redirect it below the water. The 404 is a decent choice, but the Rena
FilStar XP3 is very similar, reputedly less prone to priming
difficulties and advertised as rated for 175 gallon tanks. On the other hand,
XP3’s are often a little more expensive and last I checked the XP3 didn’t sell
with all the media you need; you need to buy biological filtration (the most
important kind) separately. The XP3 has more than one out-flow arrangement
option. In one, the XP3’s output tube runs vertically down the inside tank wall
& has little holes (a spray bar). In partially filled tanks this can be a
problem. You can cut off the output partway down & jam a piece of tubing over
it, to redirect the flow under your water. You could cut the output tube above
the holes & put a piece of tubing between the upper part & spray bar, retaining
the spray bar (yet you can custom-position it thanks to the long flexing
tubing). Bottom line: be ready to customize. Note: if the output
on the 404 or XP3 is too strong for your smaller tanks, rubber-band a piece of
fiber pad around the outflow to cut the current.
Canister Filters -
Eheim Pro II filters - you can even get'em with built-in heaters (like
the Pro II 2128)! Eheim filter media is good, but expensive. Well-made filters
that last years and years. The
Pro II 2028 primes more easily than the Fluval 404 & the output uses a
‘spray bar’ on the end of tubing you cut to fit, so it’s much easier to simply
run the output below the water surface & avoid splashing (it’s also rated for a
156 gallon tank). The white fiber pad in the Pro II 2028 is prone to ‘crud up’ &
need replacing pretty often (so if you buy a 2028 or 2128 buy extra media packs
with white fiber pads). I've seen great things posted by turtle owners; at least
one person did think they got clogged a bit easier than Fluval's on turtle
tanks. I'd look at the Pro II line, instead of those
ECCO's that show up in local pet stores. The one I'd get, the Pro II Model
2028, was around $215 online. A good choice, if money's not a factor. Sometimes
sold without media, so make certain you buy a ‘package deal;’ filter & media.
Those with thermofilters do have a sensor that goes in the tank so they are not
‘the answer’ for those whose turtles attack filters. I prefer to keep my
filtration & heater functions separate so if one breaks I don’t lose both.
- (Besides biowheels or the Eheim 2229, which also use wet/dry theory) - you'd
probably only need one. Unless the tank is to be drilled, you'll have to keep
the filter above the tank's water level and buy a pond pump to put in the tank
and push water to the filter. Uses about 1-3 gallons of bioballs as filter
media. You can see one ($200-$300)
here. Or look at
Eheim's wet/dry canister and I do hear a few great things about the 2229;
I've also heard it generates a 'wave effect' in the tank (one person thought
turtles might not like that).
h.) Under Gravel
inadequate for turtles unless hooked to a Magnum 350 Deluxe, power heads or
equivalent. Has very rarely been implicated in buildup of anaerobic conditions
under the filter plate producing toxins that have killed turtles (more an issue
during blackouts because water flow stops). Won't spread water flow evenly over
the filter plate so sludge gradually accumulates...plan to break the tank down
for cleaning every few years. Some people use reverse flow UGFs that blow crud
UP out of the rocks where the power filter can get at it, but that's out of my
experience. I prefer to remove the crud from the gravel bed by gravel vacuuming
during water changes rather than pre-maturely clogging my filter.
Fluidized bed filters
– use sand as a biological filtration
Rainbow Lifegard is an example, & has multiple optional filter modules
(covering different filtration basics) you can hook up in a linear sequence. One
person posted about great success with one hooked to a Magnum 350 with a Reeve’s
turtle tank (read about it
here; that tank is actually 48 inches by 18 inches wide by 28 inches high),
but I haven’t seen enough posts to comment. For whatever reasons these don’t
seem to be widely used by turtle hobbyists.
j.) Pond Filters
– Frankly, out of my league. Large Poly-Bead filters come to mind. Pond filters
are often sold in modular form; you can buy the media compartment here, the pump
there, etc… Some people like complete ‘all in one box’ systems so make sure you
know what you’re getting. And that your system won’t require you to do any
custom plumbing (PVC pipe, sealants, etc…) Remember that pond filters are often
designed for outdoor use so check those noise levels before you buy.
Bottom line: If you've got a Wal-mart
attitude, get a FilStar XP3 (& some biomedia!) or a Fluval 404 (and remember you
may need to fill the canister with water after servicing to get it to prime). If
you're a top-of-the-line man, get an Eheim Pro II 2028 or wet/dry. 1 XP3 ought
to be fine for up to 55 gallons. Only the ammonia and nitrite test kits know for
sure. Factor in any fish you plan to keep, as well as snails, crawdads, etc...
Put the intake and outflow at opposite ends of the tank, to create a natural
water flow that'll carry more waste to the intake.
If you don't want crud building up in a canister, see the pre-filter section.
UGF - Some use'em, but I wouldn't bother.
The awful specter of someday breaking down the tank to clean under the plate is
just too much.
V.) What is a Wet/Dry Filter?
Normal biological filter media
(say, BioMax rings in a Fluval 404 canister) are submerged. Water flows over
them and their bacteria break down ammonia to nitrite to nitrate. Cool. But
their bacterial activity is somewhat limited by the low oxygen levels present in
water. Oxygen is poorly soluble in water.
But there's a LOT of oxygen in air (21%).
So, how can we bring high oxygen to aquatic bacteria?
A wet/dry filter
is wet but not dry.
It keeps the media doused with a thin film of water, but not prolonged deep
submersion. Oxygen diffuses rapidly across the thin layer of water covering the
bacteria, who stay wet (and alive) but have more oxygen to use.
In other words, a smaller amount of biomedia can handle a larger waste load
faster than it could in a traditional constantly submersed setup (like the
Fluval 404 canister). One post I read in a fish forum said a wet/dry can break
down ammonia & nitrite up to ~ 70% faster than a normal canister filter, but
emphasized that wet/dry filters are more biofiltration focused & less capable
otherwise, so the poster didn’t recommend the Eheim wet/dry for turtles (I no
longer have the source reference). That said, the Eheim wet/dry was recommended
to me by someone working with setups at the Tennessee Public Aquarium in
Chattanooga, TN. I doubt the faster ammonia/nitrite breakdown is crucial,
although more water quality-sensitive species (like some map turtles) might be
an exception. I’m concerned during blackouts the wet/dry media may dry out and
kill off the bacteria faster, although that’s speculation and I don’t know if it
applies to the Eheim wet/dry canister filter.
One caveat – wet dry filters
maximize exposure of tank water to air. This maximizes oxygenation but removes
carbon dioxide from the water, which is bad for live plants. If you have or plan
a setup with several live plants, this may be a concern.
VI.) Can I get
rid of Nitrate without Water Changes?
Yes, but you won’t
want to do this unless your tap water comes out of the sink with nitrates
already high (say, due to agricultural contamination). The device to do it is
called a Denitrator. Basically, it creates an anaerobic environment in which
bacteria break nitrate down into nitrogen gas, which diffuses out of your tank
water. It’s thought that on rare occasion it may produce dangerous substances,
hydrogen sulfide being mentioned, but I don’t get the impression that’s a
frequent problem. These things are mostly used in tanks with such
nitrate-sensitive species as anemones in reef tanks. Another way is with live
plants. Their benefits are modest but fast growing plants (Anacharis,
hornwort) under strong lighting (i.e.: metal halide or power compact
fluorescent) may keep nitrate counts lower. In salt water setups deep sand beds
are used to create anaerobic conditions to remove nitrate, but I haven’t heard
of this being pulled off in fresh water tanks & certainly don’t recommend you
try it with turtles.
If you’d like to see a
commercial Denitrator, check out:
Want to make your own?
Check these links out.
Denitrator How-To Discussion
The main problem with
Denitrators is that you may get the idea you don’t need to do water changes
because your nitrate levels are low. Wrong! There are other harmful
dissolved substances we dilute with water changes; nitrate happens to be one you
can buy a test kit for at the pet store.
Do your water changes anyway!!!
VII.) Water Changes.
You need to do water
changes to dilute harmful substances in the water. The better filters cut down
on this, but you’ve still got’ta do those changes. For indoor setups, I
recommend at least half the water every 2 - 3 weeks for openers, and you can
monitor nitrate levels and go from there. People with larger outdoor setups with
lots of live plants are in a different category I’m not ready to discuss here.
If your filtration is good enough, you’re doing water changes to dilute nitrate
and dissolved solids, as well as to replace trace minerals, NOT to dilute
ammonia or nitrite. Perhaps you’ve heard of water ‘hardness,’ which refers to
some dissolved minerals in water (in much of the U.S., tap water is moderately
to very hard). When tank water evaporates, it leaves behind dissolved solids
(like nitrate & minerals causing hardness); if you just top off evaporative
losses with tap water (thus adding even more dissolved minerals), over time your
tank’s hardness & concentration of nitrate (& other things) will become extreme
– this is unlikely to be healthy for the turtle.
VIII.) What Test Kits do I need?
Ammonia, Nitrite &
Nitrate. The chemicals can get old; I’m not sure when to replace a kit, but be
aware. After 4-6 weeks your ammonia and nitrite levels should read close to
zero; the kit will tell you how much nitrate is acceptable. PH and water
hardness kits are also useful, although not directly relevant to filtration.
One annoyance with
canister filters is the need to periodically disconnect the hoses, unplug it,
carry it to the sink, pop the clamps, lift the top and take out the sponges to
wash off all the gunk (uneaten food, turds, plant bits, etc…). You can cut down
on this by pre-filtering.
All this involves is
putting a sponge attachment on your filter’s intake, so the sponge does most of
the mechanical filtration. You can pop off the sponge and wring it out in the
sink, or squeeze it a few times while doing water changes and sucking up the
crud (harder than it sounds; makes a cloud). Since less crud gets in the
canister, you don’t have to clean it so much. And some bacteria colonize the
If you don't want crud
building up in a canister, for smaller tanks you can get a nice sponge
pre-filter at www.thatpetplace.com (the
FILTER-MAX III) and it'll pre-filter water before the sludge gets into your
canister. I’ve tried them on my Magnum 350 Pro, Fluval 404 & AquaClear 500, and
I like'em. I’ve also tried rubber-banding large pieces of fiber floss around my
larger filter intakes; it does work, but they have to be changed more often than
the canister. I believe panty hose has also been suggested…
In the Eheim Pro II
2028 & FilStar XP3 it may be worthwhile to avoid using the fine particulate
filtration pad (Micro-Filtration Pad in
the XP3)at the top of the
media stack since it can clog quickly in high particulate tanks.
I’ve seen a number of
forum posts that read like this: ‘Recently I went to check on the tank, and my
little RES was trapped with his head sucked up the filter intake tube because
the intake strainer fell off!!! I thought he was dead! Over the next few hours
he slowly came around and now he seems to be active and eating. He did have some
hemorrhaging of the eyes. He seems okay, but of course we have to wonder if
there’s brain damage and what the long-term effects will be.’
Folks, turtles don’t
breathe water and these filters are powerful. Make SURE those filter intake
strainers are wedged on tight when you have small turtles. You can use a little
silicone or epoxy to ‘glue’ the strainer to the intake tube; they don’t bond as
well to plastic as I’d like, but could help.
XI.) Where To Buy.
There are 2 Online
vendors highly regarded by both turtle and fish forum regulars for great
selection and low price. Which is the better buy varies.
Big Al’s Online
That Pet Place
I’ve seen people favor
one or the other. I’ve used all 3 & had good results.
And that’s all I’ve got to say as
of 1-13-05. I hope it’s been helpful;)!