weird alk issues

[Bob Bennett]

During the holidays I really slacked of on my water testing routine and of course developed a control issue with my 6 year old RKL that handles dosing , I use BRS two part and dose Alk and Ca, must have not been dosing properly . For more than 4 years I have been maintaining steady levels of alk at 9dkh, ca at 450 , mg at about 1400 to 1500, can't remember last time I added any mg. , am a water changer, about 10-15 g/week. All parameters a out of wack. Using fresh Red Sea test kits, picked up a aquaforest alk test to check alk numbers.
This morning tests- alk 4.2 dkh, ca 500 plus , mag 1520, in the past week I have reprogramed and tested RKL and dosing pumps, stopped dosing ca, 3 20 gal water changes , long time user of hw marinemix Reefer which tests at alk 9.1, ca 375, mag 1520 and have added over half a gallon of alk mix.

What I just don't understand is how my alk numbers will not go up, afraid to add alk to fast, the BRS calculator gives me 475ml to raise from 4.2 dkh to 9.0 dkh, have added over 1500ml in last week, also have a montpora that is kind of my "canary in the coal mine" , kind of use it as a optical test kit, looks just fabulous !

 

[Randy Holmes-Farley Verified Community Expert]

4.2 dKH is hard to attain and is perhaps the lowest value I’ve ever seen reported for a reef tank. Consequently, my first suggestion is test error.

That said, how much dKH does w that 1500 mL in a week correspond to?

 

[Bob Bennett]

Thanks for the reply, my feelings too, never thought it could get this low, have water vol. of approx 130 gal. have redsea testing kit, only two months old, have always tested quite a bit, refill kits don't last more than 6 months, also ordered new aquaforest alk test kit, get almost same results, lowest scale on redsea kit is 5.3 dkh, af scale gets me to 4.2. Comes with water sample and both are pretty close to the 7.6 range in sample, also fresh salt mix, both tests very close, about 9.1. Recovering from Hurricane Irma, lost all fish and thought I would lose coral, but corals are all growing like crazy again, over time I have been able to keep alk pretty stable, aim for 9 +- just a little. The 1500 ml. alk is what I have added over last week, and 3, 20 gal water changes, ready to do a single 40 gal water change, had no changes in alk. test, seems crazy!

 

[Bob Bennett]

I did the 40 gal water change last night, and morning alk tests give me 5.3 dkh on both redsea and aquaforest, will order one of the mail in water sample test today, have used aquamedic water testing several times .

I really have enjoyed and have learned so much from your articles over many years, online and in print, Thanks so much!