20 gallon water change?

[sally666]

How much saltwater do you replace weekly for a 20 gallon FOWLR tank?

 

[Malum Argenteum]

Depends on stocking level, feeding, filtration, etc. Less stocking, judicious feeding, and decent filtration will help reduce frequency and volume of WCs. Maybe a couple gallons a month, maybe 5-7 gallons a week.

 

[sally666]

Depends on stocking level, feeding, filtration, etc. Less stocking, judicious feeding, and decent filtration will help reduce frequency and volume of WCs. Maybe a couple gallons a month, maybe 5-7 gallons a week.

So is the minimum 2 gallons a month? Or 5-7 gallons a week?

 

[JC1977]

You’re missing what he’s saying. Basically if it’s lightly stocked and your nitrates stay at an acceptable level you might get away with 2 gallons a month. But if you have aggressive messy eaters, overfeed, or are overstocked with insufficient filtration then you may have to do 5-7 gallons a week to keep your nitrates in check. There’s no magic number anyone can give you because every tank is different whether it be stocking or filtration feeding habits etc. You just have to figure it out as you go.

 

[sally666]

Do freshwater tanks require more water changes than lightly stocked FOWLR saltwater tanks?

 

[sally666]

You’re missing what he’s saying. Basically if it’s lightly stocked and your nitrates stay at an acceptable level you might get away with 2 gallons a month. But if you have aggressive messy eaters, overfeed, or are overstocked with insufficient filtration then you may have to do 5-7 gallons a week to keep your nitrates in check. There’s no magic number anyone can give you because every tank is different whether it be stocking or filtration feeding habits etc. You just have to figure it out as you go.

If I only have 2 clownfish and a shrimp in a 20 gallon FOWLR tank, is it okay to only replace 2 gallons each month?

 

[vetteguy53081]

How much saltwater do you replace weekly for a 20 gallon FOWLR tank?

I recommend 2-3 gallons weekly

 

[sally666]

So which one is it: 2 gallons weekly or 2 gallons monthly?

 

[TX_REEF]

10% a week is a safe rule of thumb.

 

[vetteguy53081]

So which one is it: 2 gallons weekly or 2 gallons monthly?

weekly
I do 2-3 gallons daily but I have a much larger volume

 

[Malum Argenteum]

Do freshwater tanks require more water changes than lightly stocked FOWLR saltwater tanks?

Depends.

Is the FW planted? Is it stocked the same as the FOWLR (2 small-medium sized fish and one shrimp)? Does the FOWLR have a skimmer, or refugium, or algae scrubber, or run phosphate reducing media? Does either have algae eating animals? Are the tanks using tap water or good RO water?

If what you're trying to figure out is which has less maintenance, probably FW is going to be a little less maintenance -- only probably, because algae control in SW is easier, IME (better algae eating animals available). But the water parameter maintenance in SW can be something of an ongoing task.

If what you're trying to figure out is how to get by with minimal maintenance in SW, then looking into all the hardware that can help is a good idea. Skimmers, refugia, scrubbers, chemical media, auto top off systems, and so on.

 

[Waters]

Water changes perform two functions, replenish trace elements and remove excess nutrients or other undesirables. How much or how often you change entirely depend on those two things. Some people get by without doing any water changes (and dosing trace elements). Some will do close to 100% water changes (in smaller tanks obviously). I believe in heavy water changes and do close to 5 gallons a day in a 125 gallon system.

 

[Mr. Mojo Rising]

On my 15 gallon I do 5 gallon water changes every 2 weeks