Problems with PH, Calcium, ALK, and Kalk

[wooglin]

I have a 75 gallon tank with a 20 gallon sump. I dose kalk in my auto-top off disolved at a concentration of 1tsp per gallon of ro/di water. I use a timer to move part of this dose to night hours. (Doses from 8am till 3pm, then off till 10pm. Doses at 10pm, 1am, and 4am then back on solid from 8am till 3pm. The trouble is with all of my parameters. My PH swings from 8.1 in the morning to 8.6 (as high as 8.7) at night after lights go off and first auto-dose is administered from top-off. My calcium is at 350 and alk at 3.0 - 3.5 meg. I am also dosing two part additive in attempt to increase calcium and alk. I dose it at 30ml per day. Dosed in am when ph is low. The container that the kalk is stored in has a lid, but is not air tight as the pump is in there, and it has a pipe that comes thru a hole cut in the lid.

I have tried the following:

a. Reducing the concentration of kalk ( this results in low ph of 7.8 in the am and ph of 8.4 to 8.5 at night)

b. Adjusting timer to dose during the day from lights on till about 3, then turning off dosing untill 10pm after lights have been off for 3 hours. (at full kalk strength this is getting my ph very high at 10pm when top-off makes first redose, as high as 8.7 )


How do I achieve a more steady ph, and increase my alk and calcium? Can I use Vinegar to help this problem? If so what amount? And how should it be mixed? Vinegar water, then kalk? Should it be shaken up at first, etc? I may have low CO2, if so can adding vinegar to ro/di water, then adding vinegar help? Once again how much vinegar should be added? Thanks for your help. I am at my witts end with this chemistry problem. I dont want to use reactors, and I think two part alone is too expensive on a 75 gallon.

[dragon_slayer]

How do I achieve a more steady ph

by making more setady all this:

I use a timer to move part of this dose to night hours. (Doses from 8am till 3pm, then off till 10pm. Doses at 10pm, 1am, and 4am then back on solid from 8am till 3pm.


you need to get a constant drip going rather then dump a little here and there at all different times of the day/night.

that will help your swing conciderably.

kc

[wooglin]

I wont do a drip because that does not respond to water level, and here where I live the humidity changes almost daily so a constant drip cannot be established.

The auto-topoff only dumps a larger quanity at night, during the day when the top-off turns on the PH does not move at all after the adjustment. The only reason I have the timer set to dump larger amounts at night is to keep the PH from droping below 7.9 in the night-time hours which it will if I let the system run 24/7. I feel like a daily swing from 7.9 to 8.5 is too much even though it is gradual. My target is 8.0 to 8.4 swing daily.

[Randy Holmes-Farley]

I agree that a steady drip might be better. Also, dosing only from 3 AM to noon might be the best way.

More aeration will also stabilize pH.

Finally, you can use vinegar to reduce the pH rise, but it may also reduce the pH minimum.

[Randy Holmes-Farley]

Sorry, I didn't see your last post before submitting mine. I agree that your swing is on the high side.

Do you have a skimmer?

[wooglin]

I do have a skimmer and alot of water movement, over 1500 Gallons per hour.

Would not properly removing the white crummy stuff at the bottom of a mixed batch of kalkwasser cause a problem? My kalkwasser never seems to be totally clear, and the tub allways has a crust on the top of the water.

[Shoestring Reefer]

Do you have some algae in the sump? If so, a reverse lighting cycle over the sump will help. Photo synthesis drives pH up, and during the night the pH comes down again. Having the sump lit at night, and the tank during the day, will help balance it out.

[Randy Holmes-Farley]

Would not properly removing the white crummy stuff at the bottom of a mixed batch of kalkwasser cause a problem?

It can increase the amount of impurities sent to the tank, and might make the limewater more potent than clear limewtaer, but isn't likely to cause excessive pH swings.