New 225 gallon water change schedule help?!

agent1207

Feeder Fish
MFK Member
Jan 17, 2020
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Toronto, Ontario, Canada.
Right now I have just setup a 225 gallon aquarium and moved my fish from a 100 gallon. What is the minimum water change schedule? and optimal? (being still 50%?)

Previously I was changing 50% every week, and the old parameters were
- pH 7.8
- Ammonia 0, Nitrite 0
- Nitrate 10 - 30

Aquarium stocking,
- Male Motoro Stingray 10in disk
- 2x NTT Datnoid 6.5-7in
- Red Oscar 7in

Thanks.
 

duanes

MFK Moderators
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There is no absolute regimented schedule per size tank, per stocking level, per this, per that.
The aquarist must decide for themselves what a healthy water quality is, for their fish.
And it may be different per species.
Some fish come from swamps and back waters where nitrate is elevated, so no problem at 30 ppm.
Many cichlids (my thing) come from habitats where nitrate is almost nonexistent, so for me, if nitrate hits 5 ppm, I do a water change.
I usually find an average of 30-40% water change every other day, meets my goal
 

TheWolfman

Goliath Tigerfish
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Sep 5, 2010
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I personally like to change more then 50% each water change. Say your nitrate is 30ppm and you only change 50% your going to end up with 15ppm after. That’s why I like to change 70%. When talking about large fish like your keeping your going to need a realistic target. When my nitrate hits 10 to 20 ppm its water change time. If I do a large feeding the following day I do a water change. Your liquid test kit will tell you if your behind on maintenance or not. Remember if your not cleaning your filters often enough they could be harboring nitrate too, and negatively impact your water changes.
 

esoxlucius

Balaclava Bot Butcher
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Dec 30, 2015
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Your previous schedule on the 100g seemed ok if you're happy with that level of nitrate. Just bear in mind your fish will grow which will increase bio load and if you are tempted to add to your stock now you've got a bigger tank, then obviously that will increase your bio load too.

Just test your water every now and again and check that the nitrates aren't running away with you, in which case up your schedule to compensate.
 

FINWIN

Alligator Gar
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Dec 21, 2018
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There is no absolute regimented schedule per size tank, per stocking level, per this, per that.
The aquarist must decide for themselves what a healthy water quality is, for their fish.
And it may be different per species.
Some fish come from swamps and back waters where nitrate is elevated, so no problem at 30 ppm.
Many cichlids (my thing) come from habitats where nitrate is almost nonexistent, so for me, if nitrate hits 5 ppm, I do a water change.
I usually find an average of 30-40% water change every other day, meets my goal
Some fish come from swamps and back waters where nitrate is elevated, so no problem at 30 ppm.

I just learned something new here! Always thought nitrate was kind of an absolute value to keep. Now I understand how some people claim to have tanks up to 40 ppm nitrates with no problems (which I thought was nuts).

My 225 gets 2 80-90% water changes a week with an oscar, blood parrot, chocolate and 2 synodontis catfishes. Probably overkill but the cichlids are still growing and I'd rather not do endless rounds of water testing without reason.
 
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Toiletcar

Goliath Tigerfish
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Jun 5, 2008
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Few other things to consider w/ how many water changes:

1.Feeding. I don’t feed my cichlids every day. They don’t need it. Feeding less will lessen the waste and nitrates will stay down.

2. Filtration. What kind of filtration? More is always better. Clean out canister filters w/ tank water regularly. Nitrate levels can really build in them.
 
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