What am I?

[FragOutpost]

Adding RO top off water will not affect alkalinity. There are basically two ways to reduce alkalinity. One way is to wait for the organisms in your tank to consume it (coraline, sps, clams, lps, and other calcaerous skeleton building creatures) and the other way is through precipitation which is basically what you are doing by adding calcium. Water can only hold so many dissolved solids. Adding only calcium will force out some of the alk. Caution should be taken though as doing this too fast will cause too much precipitation. Are you adding all 5 gallons of top off water at the same time? Top off should be added daily to reduce the swing in salinity. Dripping top off water is best but not necessary, although small frequent amounts are much better than large amounts every few days. I usually add half of my top off water in the morning and half in the evening.

[Teeka01]

Okay I did not know this. I can start doing a gallon a day.

[FragOutpost]

For example - it takes around 1-1.5 gallons of evaporation to increase my specific gravity by .001 in about 100 gallons of water. My tank evaporates almost 1.5 gallons per day in the summer. If I was to not add any top off for three days then my SG would rise from 1.025 to 1.028. I try to keep it between 1.024 and 1.025. Another thing to remember is that RO water has a low ph and adding it in large quantities could cause a swift drop in your tanks ph by 0.1 or 0.2 or even possibly more.

[Teeka01]

Thank you, I always learn so much from you.

[FragOutpost]

Glad to help in anyway that I can.

[Teeka01]

Frag I have a question. First let me tell you todays results Calicum 410. Alkalinity is still 14.4. Do you think part of my problem maybe gas exchange? I have a 29 tall tank. Someone at the LFS said that I may need to add a couple air stones to my tank. I also have my skimmer on max air.

[FragOutpost]

Is your PH low? Do you get a lot of surface agitation? Gas exchange is the solution to low PH caused by excess carbon dioxide. Carbon dioxide turns into carbonic acid in water. The way to tell if this is your problem is to take a cup full of water and place it outside with an air pump aerating it for at least 12 hours and test your PH. If your PH is higher in the sample that was aerated outside then your tank has too much carbon dioxide. You can try aerating your tank with an airstone but this will only equalize your tank with the air in your house. Sometimes people who live in more modern airtight homes can experience a buildup of carbon dioxide in the air inside.