2 part dosing mystery

[reeferparty]

So many of you here that are active may probably know that I've been trying to dial in my 2 part dosing for some time now. I am getting close (..I think) ¯\(°_o)/¯

I have my doser set to dose 116.3ml of alk for 24hrs every other hour. Last night I tested my Alk at 8pm and it was at 7.1dkh so I raised it to 8.3dkh over the course of 4 hours. I don't usually test during the day due to work but I tested this morning at 10:30am and it dropped it 7.3dkh. I took no action and waited until 8pm to check again 7.3dkh. I manually dosed back up to 8.3dkh.

Ph 8.1-8.3
Ca -420 stable dosing 174ml for every hour for 24hrs in between Alk.
Mg -1460

It appears that maybe my tank doesn't like to hold Alk stable at anything over 7.5dkh -ish. But I'd like to have my Alk/ca balanced at 8.3dkh/420ppm. It also appears that between 10:30am and 8pm, my doser kept Alk stable.

Couple questions:
Should I spend the next day manually dosing throughout the day to keep it stable at 8.3dkh? Or should I set my doser to dose more and to match my ca dose?

 

[reeferparty]

Just tested my Alk 4 hours later and it's back down to 7.8dkh

 

[Randy Holmes-Farley Verified Community Expert]

That's not especially surprising. The more alk you add the higher the consumption rate for it.

 

[chipmunkofdoom2]

Personally I would try to dial this in with your doser. If your carbonate alkalinity keeps trending down to 7.3 dKh, that means you're dosing enough to maintain alkalinity of 7.3 dKh. If you want to maintain higher levels, your doser needs to dose more. Maybe start by increasing your daily dose by 10% and see where your carbonate alkalinity is after a few days. If that's still not enough to maintain 8.3 dKh, increase the daily dose a bit more, then wait and see what happens again.

Additionally, raising carbonate alkalinity from 7.1 dKh to 8.3 dKh in 4 hours is a substantial increase in my opinion. I don't like to change my carbonate alkalinity more than 0.5 dKh in an entire day. I wouldn't advise making such large adjustments so quickly, especially if you have SPS in your tank.

 

[reeferparty]

Thanks randy and everyone else for your continued help/advise and patience! I have finally got my dosing dialed in and my parameters stabled without having to manually dose every evening. Now I can focus on feeding more to get my nutrients up! [emoji28]

 

[Xclusive Reef]

That's not especially surprising. The more alk you add the higher the consumption rate for it.

Randy question on your 2 part alk / cal DIY.. IS there anything different from Red Sea, ESV and your DIY ? are there certain elements that we should be adding is using your 2 part?