alkalinity demand

[BigJay]

My tank is demanding about 1 DKH every day. Since I've been dosing .5 DKH of two part, this became a problem with testing this week.

My system is probably about 200 gallons of water. Is this level of consumption normal or reasonable? My bioload would be considered moderate. Four dwarf angels, pair of percs, lawnmower blenny, fire fish, and six chromis. I have maybe a dozen frag size corals, nothing big.

 

[blide]

Do some research and you'll find all the details, but here's a short summary:

Your fish won't have much to do with the Alk. It'll be your corals and algae that change your Alk day to day.

Try adding Kalk to your topoff water it should help stabalize things and reduce adding chemicals day to day.

 

[DaveJ]

Jay... toss out some volume numbers of usage instead of the dkh number. Also the type of 2-part you are using is important.

For example.. my main system, the 140/65/sump and fuge utilize about 200ml of alk and 230ml of cal per day. My 92 uses about 50ml per day.

Your bioload will determine the volume you need to dose, some people it will be small, others it will be rather large. The goal as always is stability so as you start dosing larger volumes, its more important that you add it as frequently as possible in smaller amounts to avoid the spikes.

 

[BigJay]

@DaveJ wrote:

I'm currently using 150 ml of each solution per day every morning of Randy's two-part recipe 1 (from bulkreefsupply) for 1DKH.

I've been slowly adding four teaspoons of RO/DI dissolved baking soda at night for an extra 1DKH.

Alk has been creeping up the last few days:
Saturday: 7.0 (waterchange with 30 gallons 9DKH adjusted water)
Sunday: 6.5
Monday: 7.5
Today: (hopefully) 8.5 or 9

It seems like a lot, but I've been spreading out the doses 12 hours apart (6 am and 6pm every day). Once I hit 9 DKH, I'll stop dosing baking soda, and add 75ml of two part twice per day. I'll probably pick up a pair of dosing pumps to do this automatically.

I just can't believe my demand is this high, all I have are a dozen or so small frags. You have so much more thriving SPS coral than I do. :wink:

 

[psteeleb]

I had issues with ALK getting used up a lot faster then Ca for the first year. I'm somewhat convinced that the rock and sand (and the micro organisms they harbor) have to reach a PH/Alk ballance with the rest of the system, and this can take time. This can go both ways, for example you could be releasing Ca so it appears that it isn't being used as fast. You could also have slightly acidic rock or sand that is using up Alk as a buffering agent. Either or both should reach a point of ballance eventually.

I'd just give it time and try to keep on top of it.