Water Changes for SPS Tank

mchammer

Member
Is once a month too long for water changes in a SPS tank. I've always changed my reef tank water once a month but my old tank was soft and LPS corals and I never had a problem. Corals grew great, in fact the soft corals took over the tank and that made me decide on SPS only (easy to crop when needed). I have a low bio load right now just 4 fish (2 Clowns and 2 Damselfish).

Thank you in advance
 
depends on the size of the water change as well, what your corals are consuming etc.

even if you have a large bioload and you do a large water change 1 a mo things can go very happy, i like weekly or bi weekly 10-20% range for stability....but i know others that do more/less/none......every system is different and you wont know till you try.

I recently went about 5 months without changing the water ...moved and am building new tank while old tank is still up and running.....corals did fine for about 3-4 months....lost a little color but still grew and things got dirty, did a large water change and things started getting happier very quickly.

if your exporting the nutrients (macro algea, GFO/Carbon, Biopellets, skimmer) etc and mainting ca/alk/mg etc that is the big goal.
 
Again.....your water tests will tell you what you need to do.

I disagree with this. Generally I view water changes as good for the things that you can't test for and don't know. In a tank where nitrates are ND and phosphates are kept low, exactly what tests do you think will tell you it's time to do a water change?
 
I disagree with this. Generally I view water changes as good for the things that you can't test for and don't know. In a tank where nitrates are ND and phosphates are kept low, exactly what tests do you think will tell you it's time to do a water change?

Well I disagree with waiting months to do a water change just cause your trace elements and phosphates are fine.
 
i disagree with this. Generally i view water changes as good for the things that you can't test for and don't know. In a tank where nitrates are nd and phosphates are kept low, exactly what tests do you think will tell you it's time to do a water change?

+1
 
I change a couple times a month. When I reduce down to a monthly basis I see a decline in the appearance of my corals then when I do the water change everything looks great again. Tests all appear fine regardless but why stress my corals out to the point they start to appear "off" just to save myself 15 minutes once a month. I used to do them weekly and I would again if I had a 15 gallon bucket but it's easier for me to mix it up 30 gallons at a time.
 
I do water changes primarily as a way to siphon detritus from my sandbed and sump. So I do them as often as is necessary to prevent significant detritus buildup. I believe the nutrients contained in the accumulated detritus are much greater than the dissolved nutrients contained in the water. IMO a water change done without siphoning is a waste of good saltwater.

Reestablishing proper mineral concentrations is an important, but less critical benefit. An occasional water change should be all that is necessary for this.
 
In my opinion... it all depends on how stocked your tank really is.. If you have a small bioload of fish then 4-6 weeks is fine. If you have medium load then 4 weeks is fine, if you have a heavy heavy load then 2-4 weeks is fine. Also, take in to account the amount of corals you have which will use up trace elements.

I think it's more important to make sure you skimmer is working at 100% all the time and that means cleaning the venturi and hose every 2 weeks - making sure your carbon and sock are changed on time. With that said I try to do a water change every month but see very little effect in going up to 6 weeks. My tank is 120 gallon with very small bio load compared to the others i've seen.
 
Just like you, I had a 75gallon of soft and LPS coral before and only did water change once a month with no issues. Now with half of a tank full of SPS and the other half LPS and softies and 9 fish, I do bi-weekly 20% water change. However, I have a much better skimmer to help out. My SPS are pretty happy.
 
Well I disagree with waiting months to do a water change just cause your trace elements and phosphates are fine.

Wait, are you disagreeing with me or your earlier post... At what point did I imply someone should wait months for a water change? How would one know if their trace elements are fine? Also, what test kit will tell you it's time to do a water change?


What I'm saying is no test kit will tell you when to do a water change in a tank with low nitrates and phosphates. So, it's a good idea to do them as balance for the things you can't test for. I do about 20% ever 2-4 weeks, depending on how good I'm being ad my travel schedule.
 
1st and 15th of every month 10%. Sometimes I get busy and do it once a month. Haven't seen any ill effects if I do it once a month. Then again every system is different. I would do at least 20% monthly, its up to you with once or twice at 10%
 
IMO... small, frequent water changes to maintain ion balances works well. There are many more efficient methods to reduce nitrate and phosphate. Somebody said it above... it's to "maintain the things we don't test for". I like the small and frequent schedule to reduce the chance of stressing the system. I do ~12% every week buy skip a week every once in a while.
 
If you could change as much water as you loose in evaporation everyday would be ideal. I do 20% every 2 weeks
 
I have no problems with doing water changes. I've always done once a month for my old tank but like I said, it was soft and LPS corals which thrive on less then perfect water. I haven't kept SPS corals before so I just wanted to know if people with SPS tanks change their water more often. Looks like it runs the whole spectrum from once per week to once every 6 months. I'm going to start every two weeks 10 percent which is 15 gallons and see how the corals respond. Some people answer my next question which is "What is better small frequent water changes or large infrequent water changes"

Thank you all for the great input.
 
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