Hey sump users: Do you do less water changes than canister users?

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IMHO you can keep more fish in a tank with a wet/dry sump than the same tank with a canister mainly due to the extra oxygen the wet/dry sump adds to the water. Canisters are sealed systems and add no oxygen to the water. The beneficial bacteria in the bio portion of a canister actually consumes the oxygen in the water to some degree. The bio balls in a wet/dry sump does a great job at breaking streams of water down to drops of water and the mechanical interaction of the water and the bio balls exposes huge amounts of water surface to the air. This huge water surface area allows for a lot of gas exchange between the air and water area and provides a lot of oxygen to the water at the point where the beneficial bacteria consume it leaving plenty of left over O2 for the other aquatic inhabitants.

I believe a tank with a wet/dry trickle sump, in general, is able to handle a larger fish population than a comparable tank with a canister... especially with non-planted tanks.

That's a far-fetched conclusion. Bacteria will grow where they can attach to a surface. Be it submerged in a canister or in a wet/dry sump. You speak as if a canister is filled with stagnant oxygen-deprived water. That is hardly the case. The only reason wet/dry filters rely on high levels of oxygen is because they use media with poor surface area (bio balls). Why do you think people always say don't use bio balls in a canister filter, and to use porous ceramic media instead? Surface area. That's why.
 
You actually have to do more water change if you take into account of evaporation loss
 
+1
I have both. Sumps lose inches of water while canister is hardly noticeable. Types of filter does not affect WC schedule.
 
there is a difference between doing a 50% water change and topping off evaporation. Sumps are far better than canisters, they are more customization able, adaptable and are more easy to maintain, with a good quality media like ceramic rings and an increased amount of oxygen you can keep more fish in a tank with a sump than with a normal canister. If you use the matrix media from Sachem you would have to do even less water changes as this media also breaks down nitrates.
 
there is a difference between doing a 50% water change and topping off evaporation. Sumps are far better than canisters, they are more customization able, adaptable and are more easy to maintain, with a good quality media like ceramic rings and an increased amount of oxygen you can keep more fish in a tank with a sump than with a normal canister. If you use the matrix media from Sachem you would have to do even less water changes as this media also breaks down nitrates.

Mmm.... Not really, or at least not without a catch. I use Matrix in my sump for my 300 and in the canisters on my 135. It's a great media and I highly recommend it, but denitrification is not one of it's strong suits. Seachem even recommends flowrates of around 50 gph to see nitrate reduction with Matrix and denitrate. I set up a phosban 550, filled it with denitrate/matrix and have been flowing just about 50 gph through the reactor. Will I see nitrate reduction? Maybe? Maybe not. In a month I'll know myself for sure.

A properly setup canister will handle a systems bio-load just as well as a well planned sump. I run both types of setups and both have there advantages. The increase in system volume is the biggest edge a sump has, but as long as you have enough surface area to support the proper sized colony of bb, canisters may be all you need.
 
I've met a few people on mfk who use big 40-60g sumps and they all told me that they do less WCs and are able to keep a lot more fish in their tank with a sump than before when they were using canisters. Is that true? How often do you guys need to do water changes?

I've only used canisters like FX5 before but I plan to use a sump for my next big tank. I want to buy a 240G tank and use a 60G sump with an FX5. I want to be able to do less frequent WCs so I hope that what those sump guys told me is true. Some guys told me they only need to do a WC once every few months and clean or change the filter sponge every week. Does that sound right?

The theory of keeping more fish & less water changes is correct but not ideal.
Water changes done on a set daily to weekly basis is ideal and also beneficial for
your live stocks' health and younger or smaller fish's growth rate. Also water
changes are done to keep water parameters [ammonia, nitrites, nitrates & etc]
in check to keep your live stock healthy and reduce the possibilities of diseases
& etc... If your planning to run a wet-dry/sump filtration system you can stock
the system heavily with bio-media & live plants which will help keep your water
parameters in better check and thus in theory lower the amount of water changes
done... Other ways to keep water parameters in check is to not over feed. Over
feeding causes more waste & phosphates which contributes to excess & unwanted
nitrates. Even with a wet-dry/sump filtration i wouldn't prolong the period of water
changes, instead reduce the amount water being changed & or maybe have
multiple amounts of water changes of about 15-25% through the week...

When I had my 270g I ran a 120g sump [closed loop system] filtration and inside
the sump filtration it was heavily loaded with bio-media & live plants & a low
wattage UV-sterlizer... I did one 40% water change or two 25% water changes
per week & it kept my water parameters in check and kept my water crystal clear
diamond pristine like Arrowhead mountain spring water!... lol

Hope this helped you a bit, if not ehh... I don't know... Maybe someone else that
is more knowledgeable then myself can help you & explain it better...
 
In addition to all the wonderful advice being given, irregardless of the type of filtration you have, weekly WC are essential to replace depleted micro and macro nutrients/minerals that fish need for proper physiological functions such as the digestion of food. The lack of certain micro/macro nutrients in the water column can increase stress in fish which in turn can lead to other serious issues such as a weakened immune system...... disease... etc.

Keep up the weekly WCs. It's one of the best things you can do for your fish.
 
I have a 150g cube with a tigrinus and 4 zebra plecos. I grow lots of live floating plants and just pull out bunches of them every so often. I do a water change and vacuum the gravel every month or so? Sometimes longer. I plan to move them to a 90g and repurpose the 150 eventually I think.
 
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