Dosing, pH, and alk control

[Velodog2]

Ok I'm working this all out. See what u think.

I got my Jebao DP4. I know it is cheaping out on a critical piece of equip but I believe, for now, that dosers are commodities that should not command the prices charged. There is no "R&D" involved in a plastic box holding a couple of circuit boards, stock LED display, and some sourced peristaltic pumps/motors that can be found for $10 on the interwebs (yes, I opened it up to see - pics available). Regardless, I have it plugged into an Apex outlet as a "kill switch". The Apex monitors the pH and immediately pulls the plug if it spikes above 8.55 and sends an alarm in the case that the motors stick on somehow.

My 18 gal tank has been using increasing amounts of alk and it had become a problem for maintaining pH. I was topping off with kalkwasser with a float switch and adding 30 ml of BRS two part and still just keeping alk at barely above 8 dKh. In that scenario even if I dosed alk in the morning my pH was beginning to often top out at near 8.65 and my montis and birdsnests were very unhappy about it to the point of dying to prove it (I don't know who decided acros were the prima donnas of the reef tank. They just motor thru everything without complaint).

So I stopped the kalk additions and programmed the controller to add 30 ml of alk in 10 increments from 6 am to 11 am when the main lights come on. I would like to start earlier but it turns out the doser pumps are noisy and sometimes people have to sleep in the bedroom the tank is in. The 30 ml of Ca is added in 5 doses from 2 pm to midnight. This much has been keeping Ca at barely 400 ppm.

Just started this routine and not sure if I will be able to keep adequate levels without kalk, but my initial objective was to get pH under control. So far it has been topping out at just 8.48 in the evening which should be ok.

 

[Randy Holmes-Farley]

This plan sounds fine to me. You can meet any demand with a two part, so there should be no limitation, except perhaps if your doser runs 24/7.

Calcium is fine to dose less frequently if you want, since it doesn't decline much in a day, and doesn't impact pH when added in individual large amounts.

If the pH does not drop further, I'd suspect a pH measurement error. When was the last time you calibrated it? How old was the fluid?

If you want calcium higher, you can give it a one time boost to your target, then use the doser to keep it there. The new salt water for water changes may also ruin a bit low, and if true, you can boost the salt mix itself prior to using, if desired.

 

[Velodog2]

Thanks for the feedback. pH topped out at 8.38 tonight. It's a new probe and was just calibrated about a week ago when I installed it so it's probably accurate. I have no reason to think it's not considering how much calcium precipitated on my equipment recently and how unhappy my coral is. My prized reefgen orchid stylo has a bright white dead spot the size of a dime as of this morning. I hope I'm on the right track with the cause of this stuff and can just let things stabilize. I've never had problems like this before.

 

[Randy Holmes-Farley]

OK, that's reasonable. Sorry about the coral.

 

[kutcha]

could it be that you have hit a point with your livestock were you can not supply enough calc/alk to mantain the levels you want? maybe it is time to sell a colony? IDK i am jsut guessing i have see npeople with large tanks that overstocked there tank with to many corals and they couldnt keep up with the demand

 

[Velodog2]

Kutcha the thought occurred to me that I could be reaching that point though the colonies are generally not that big. As Randy says tho, now that I have the doser and have killed the kalk I can worry less about pH spikes and essentially set up an alk and Ca IV line if I have to.

Things have stabilized the past few days with alk at 8.4 and Ca at 400 dosing 30 ml of each per day. Both acceptable. I don't know if 30 ml in an 18 gal tank is a lot or a little. I modified the add times a bit by putting four of the ten alk shots between 10 and midnight to give the pH a boost just as it's starting to drop. PH is now cycling from about 8.12 to 8.40. Still need to check the probe calibration this weekend.

I do need to upgrade my salt brand when this bucket runs out. It mixes up to 10.7 and 390 alk and Ca.

Corals are behaving more like their old selves. May have to frag up the birdsnest that got damaged but it grows fast so no big deal.