Chemistry for Seahorse Tank


New Member
Hey guys! Still working on getting all the chemicals in my tank stable. Hoping you could help me out.
Heres the specs of my tank before I get into my problems!
-36 Gallon Bow Front
-It was originally filled with tap water and salt that I premixed. (I used dechrlorinaters and such) But I now have RO/DI pre-mixed SW and FW for topping off and water changes.
-HOB Filter for up to 70 gallons
~With the sponge, carbon bags, phosphate remover (wasn't added until after first readings) and another bag that is mesh and filled with tan-colored pellet things (what are those for?)~
-2 x 180 GPH pumps
-36 lbs of Live Rock
-Live Sand
-Lots of plastic hitching plants
-Growing some Caulerpa Prolifera (still small though)
Will be adding a skimmer next paycheck (any recommendations would be nice)
After the spike and fall of my ammonia and nitrites I did a 30% water change (with pre-mixed RO/DI SW)
Here were my readings a few hours after the water change:
-pH 7.2
-Ammonia .10ppm (This has been staying at this reading for about 1 week, after it spiked and lowered)
-Nitrite 0ppm
-Nitrate 160ppm
-Phosphate 10ppm
-Carbon Hardness 18 dKH
-Calcium 300ppm
I added MAX MARINE BUFFER (1 scoop per 10 gallons), ACI CALCIUM (5mL per 10 gallons), and I added a Phosphate Remover bag to my filter.
Here are my readings today:
-pH- 7.4
-Ammonia .10ppm
-Nitrite 0ppm
-Nitrate 80ppm
-Phosphate 8-9ppm
-Carbon Hardness 18+ dKH
-Calcium 300ppm
Should I be adding more buffer and calcium and see if that regulates the Carbon Hardness? How long should the Phosphate remover take to remove all the phosphates?
Why isn't my ammonia settling at zero yet? Even after a water change?
By the way, I should mention that I had what I believe is called a "diatomic bloom". I have an orange color on the tops of my live rocks and my plastic plants and some on my sand. Should I be worried? Will this go away on its own?
Thanks for your help! Not getting my seahorses until everything is PERFECT!


I'm assuming your tapwater contains chloramine, and your test kit measures TOTAL ammonia, so it appears that you still have ammonia in your tank, however it's likely bound by the conditioner. Look for a kit that measures NH3 only.
Your pH is too low...what time of day did you test? You shouldn't test first thing in the AM or whenever you turn first turn the lights on, as the pH will be low because the tank has gone into normal respiration, gives off CO2 and drops the pH. Before you add SH, you'll want your pH to be at least 7.8 (up to 8.3 is fine). Your high nitrates may be adding to your pH issue.
Find out what the PO4 scavenger you're using is. If it's Ferric Oxide, it can irritate the gills of fishes with closed opercula (such as SH). However, if it's Ferric Oxide Hydroxide, it's fine to use.
Sounds like your diatom bloom may be starting if you see rust colored "dusting"...leave it alone, and let it burn itself out (usually takes a week or two).
Finally, when shopping for SH, do yourself a HUGE favor and only get TRUE captive bred specimens...not "tank-raised", but true captive bred SH from a reputable breeder or hobbyist breeder. These SH will come to your door happily eating frozen mysis and are free of disease (SH are very susceptible to bacterial infections).