How much do you dose?

[asylumdown]

I've been having a heck of a time keeping my alk above 7 recently. I'm using what I believe is known as Randy's two part recipe - an alk solution of 1 cup per gallon of baking soda, and a calcium solution of 1 cup per gallon anhydrous calcium chloride. I recently added a 3rd dosing pump to deliver a magnesium sulphate/chloride solution as I couldn't keep mag up with water changes and occasional hand dosing anymore.

My dKH has been hovering around 6.7 for weeks now, and fell as low as 5.8 when I wasn't paying attention because of school. I thought it was my test kit but I've confirmed it with a different brand. My calcium was also stuck at 380, when I normally prefer it to be over 400. I'm presently dosing 130ml of the alk solution, and 115 ml of the calcium solution a day, and nothing is budging. It bumps up a little after a water change, then falls back down. If I didn't have 4 gallon dosing reservoirs, I'd be refilling them weekly at this point.

The corals are growing like weeds, but one of my birdsnest colonies took a beating when the alk got down below 6.

am I simply not dosing enough, or do you all think something else could be going on? 275ish display, 375ish total volume, almost exclusively SPS.

[Zoaelite]

Only unseen solution I can think of is your calcium is elevated causing calcium carbonate precipitation thus lowering the alk. That being said if your corals are growing like weeds I doubt your levels are wonky.

I have a feeling your deficiency is due to a whack load of coral, I was dosing near 150 ml of both solutions when my 120g was running. Might be time to choose yourself a fancy little reactor.

[1eyedjyde]

I tried to use randys two part recipe when I started using bulk calcium but I had to dose more than double what I usually had to so I increased the concentration of the calcium to 750g per gallon and the alk is 2 cups of soda ash per gallon as per the brs guide. I now dose 90 mls of cal and alk per day for a 120 gal moderately stocked with special and lps.

[Bblinks]

I agree with Levi, since your corals are growing like weeds(which is awesome), its consuming a lot more supplements . I would test the three for the next few days and figure out how much more it's up taking then manually adjust the parameters back to where you like it to be, boost up the dosage to match the extra growth and test the following week. Btw make sure you don't dose more than 100 ppm for calcium and mag per day and no more than 1 point for DKH.

[e46er]

Randy's receipes are over double the concentration of your solutions

2 1/2 cups /gal of cacl for calcium
2 1/4 cups /gal of baking soda for alk

http://www.advancedaquarist.com/2004/4/chemistry

[daplatapus]

What's your Mg at? I found with my tanks, if my Mg wasn't 1400+ I couldn't get my Ca or dkh to climb at all. Once I had my Mg steady at 1400-1450 it was easy to get my Ca and dkh right to where I wanted them.