Jump to content

Rule On Water Changes For 90 GAL w/ 45 GAL Sump/Refugium


Recommended Posts



Is there a common rule of the saltwater thumb on how often, or how much of a water change to do for a 90 GAL w/ 45 GAL Sump/Refugium?


So far I have not had a problem with water params. in the past 4-6 week of my tank being set-up. I have several filter feeders, more then fish, and a bang-up clean-up crew that are staying right on top of things. My skimmer is working and not pulling hardly anything out. My refugium is full of cheato, and other micro-alge. This is very early in the game I know, but besides the green hair alge and the red hair alge I have only had patches of brown on my live sand bed weeks ago. but now the emarald crabs and blue leg hermits have eaten all of that.


Should I then do a 10% - 20% water change or what?


My flame scallops ( I know, don't have flame scallops) are doing awesome, the color is bright and they have taken up shop in their own territory and move from place to place every few to several days. I also have (1) green carpet and (4) bubble tips and that are very happy and are feeding most of the time. I just hate to play with it too much and screw things up.


Thanks in advance



Link to comment
Share on other sites

Rule of thumb is 10-20% a week.


I think that most would call green hair algae "a problem" and it is caused by having too many nutrients in the tank. So you either have phosphates or nitrates that are built up in your tank. Water changes dilute both of these nutrients.


Most people find it difficult to keep anemones alive before their tank is 6 months old. Bubble tips are a lot easier to keep than carpets. Watch them carefully for any signs of shrinking or decay. Having them "ball up" for a day or two is normal, but keep a close watch on them anyway. Make sure you read this link http://www.karensroseanemones.com/ for good information on how to care for anemones.


Good luck


Link to comment
Share on other sites

Yeah I would say 10-20% a week is the norm. Some thou will argue with you about that and say that other things figure in to it and smaller/less WCs can be made.


But since you are new I say stay with the 10-20% rule EVERY WEEK. This will also help you make up for any over feeding or other minor mistakes that can lead to larger problems.

Link to comment
Share on other sites

I would always do MORE than necessary to start and you can always back down, on a larger SPS dominant I do 10% per week and have in the last few months backed it down to every other week after 2 years of once a week.


On my smaller soft coral tank I do 25% per month as these corals are not as sensitive to changes and can tolerate water of less quality. Each tank would be different just remember more is better and you will find the right choice, all dependant on many things, like nitrates, purity of water, load and many many other things.

Link to comment
Share on other sites

I have a 90 and also a 20 or 30 gallon sump and when I do the WC I just do about 25 to 30 gallons. I also just do in monthly as it is easier that way. Tank has been running for about 6 months maybe longer and everything is doing great. SPS are even growing. Good luck with the set up.

Link to comment
Share on other sites

Pull out some of the cheato as it grows. If you can take the rocks out that have hair on them and scrub them up well. Use the water your taking out of the tank to give them the scrubbing then toss out. I did 1/3 changes every 6 weeks, but that was after several years. Do your 20%change a week till you get the hair gone. In 6 months you can back off. Don't push it. If I read correctly, your just a couple months setup. Be patient.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Create New...