Fish Tank Supplies

5 Responses to “How Much Water Should I Change In My Salt Water Fish Tank?”

1. Jhavid F Says:
   March 4th, 2008 at 2:26 am

   OK first of all didn't rule out phosphate as a problem i didn't think this was my problem yet all my levels were fine. the phosphate caused me to loose lots of bacteria on my live rock as well as a fair few fish including my praised flame angel : (. also make sure your filters are working properly. IMPORTANT do not clean it out. however you can clean out the final layer of your filter which will be a sponge or similar used to collect the very fine particles just before the water reenters the tank. these particles often cannot break down in filters so you must remove them manually(not fun). another thing to check is ammonia nitrite basically consumes the ammonia and therefore breeds and becomes abundant. so you need to look at ammonia first. now to lower ammonia feed less, have less fish, have more live rock with good amounts of purple and pink bacteria(i suggest a product called purple up), better filtration. now the thing that eats nitrite is nitrate so possibly turn off your protein skimmer for a week (as it removes nitrate) so as to create a small amount of nitrate which will eliminate the problem if nitrite and then be easy to get rid of by turning the protein skimmer back on (be sure to have a good protein skimmer. i stress check for phosphate and use the product "purple up". as far as water changes the general rule is change between 15%-25% of your total volume every month (less if you have a good, stable system running) if you have a spike(quick growth in nitrate, nitrite or ammonia) or ust bad levels it is ok to change up to 50% per week i would do a change of 25% 2 times a week. also do not touch the substrate while doing this you will unbalance the creatures that live in it ( you probably dont know they're even there and it will kick up lots of bad stuff into the water with a number of bad outcomes resulting.
   References :

2. craig b Says:
   March 4th, 2008 at 2:34 am

   You don't need to change any. You NEED to get the chemistry right. You don't have enough bacteria in there to assimilate the nitrites. Do you have other fish? You need the constant circulation and growth of bacteria doing what it's supposed to do.
   I would say that you don't track and/or graph your tank's chemistry. Start. This will tell you what is going on in there.

   I had several salt-water tanks and didn't change water at all. I never had to. I kept my chemistry correct and just added fresh water for make-up. If you HAVE to change water - you're doing something way wrong.
   (it's all about chemistry!)

   EDIT: I read Jhavid's answer above and it's flawed. Nitrates are not removed by nitrates. (CRAP!) There is bacteria that lives in the filters and all over that will assimilate ammonia into nitrites then into nitrates then into NH3 - fertilizer. Live plants / plankton will assimilate that. Even light to some extent. Again, it's all about chemistry.
   Nitrosomanus (?) bacteria works on ammonia to nitrites
   Notrobacter bacteria works on nitrites to nitrates
   Plants work on nitrates
   Slow - slow - slow is the key
   References :

3. Patrick K Says:
   March 4th, 2008 at 3:32 am

   If this is a new tank then let it cycle before adding any more fish. If you still have fish in it now then do enough of a water change to bring the Ammonia and Nitrite levels down to 1ppm. Because this is a salt water tank it might be best to do nearly all in one water change if the levels are extreamly high like 8ppm. If you don't have any fish right now then don't do a water change. Just let it finish cycling. Once your Ammonia and Nitrite level are 0 check your nitrates and if needed do a water change that brings them down to below 20ppm. Again it is best to do this in just one water change. If this tank is several months old then you might need to improve on your Bio filter some. You should have at least 2 inches of argonite sand.

   To keep the levels down you will need to do water changes. You should alway have an ammonia and Nitrite level of 0 after the tank has cycled. I prefer to keep my Nitrates below 10 but fish can handle them up around 40ppm. Phosphates are not a problem unless you have Corals. If you are going with a reef tank then you will want to keep Phosphates below .5ppm.

   Good Luck

   PK
   References :

4. Steve G Says:
   March 4th, 2008 at 4:03 am

   15-25% water change each day for a week that is about 7-9 gallons out of your tank good luck and get some more clownfish they are the cooliest fish in the world
   !!!
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5. cotontail2 Says:
   March 4th, 2008 at 7:34 pm

   Do you have live rock or corals? If so, I would do a 20% change, refill and let the tank cycle for a few weeks (like Patrick said). Do not add any critters, and keep your feeding at the bare basics. (if you have remaining fish). And test, test and test the water! I would recommend getting a larger tank. The smaller your tank, the smaller your margin for error. Go as big as you can afford. I have a 125G and want to go bigger. It is addicting.
   One good way to keep nitrites down is live rock and bio-wheel filters. Make sure your carbon filters are OK. I have to change mine more often because I have a higher fish load (13 fish in 125G) Once again, Test, test and test!
   References :

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