2 Part Dosing Questions

[Patrick Cox]

Hello,
I started my primarily SPS tank in Feb, 2016. The tank is about net 90 gallons of water including the sump and minus rock volume. I started with a shallow sandbed and Tampa Bay live rock. I had on and off problems with algae for a long time so in April of 2018 I removed my sandbed and a piece of live rock that was covered with algae and then I added some move live rock. I probably have 60 lbs of live rock right now. The tank is also pretty full with hard corals.

I have been trying to keep my alkalinity around 7.5-8.0 and then I just let the Calcium fall where it does and then I try to keep Mg above 1300.

I dose ESV 2 part on BRS 1.1ml dosing pumps that split the dose every hour across a 24 hour period.

Now to my issue and questions...

Back in mid July, I was checking my alk about once per week and I discovered that my alk was all of a sudden down to 6.6 dKH. At the time I was dosing 31ml per day of ESV 2 part. Since then I have closely monitored my alk and as of today I can report the following...

1. I am now dosing 77ml per day. So my dosing has more than doubled since July. My corals do seem to have really taken off and I have a lot of coralline algae growing in the tank. So this seems like I am on the right path.


2. The issue I am having and really my main question is - my alkalinity seems to fall during the day and then rise at night. I have never experienced this before but I assume that it's because my tank was not consuming that much alkalinity until now. But I am having a hard time figuring out what I should be dosing because I keep having to supplement in an effort to keep my alkalinity stable. Maybe I don't need to do that? So is it normal for alk to fall during the day and then rise at night if I am dosing at the same rate every hour over a 24 hour period? Maybe I should change my dosing schedule?

So thanks for any thoughts/suggestions!

Pat

This picture is from about a month ago and the tank looks different today...

 

[carrico]

Patrick had a problem similar to yours, and what I did was split the doses every two hours. For a week I did tests at different times, with the light off and on and after that division my alk remained the same at all times tested.

 

[Patrick Cox]

Patrick had a problem similar to yours, and what I did was split the doses every two hours. For a week I did tests at different times, with the light off and on and after that division my alk remained the same at all times tested.

So just to clarify - are you suggesting to dose every other hour instead of every hour? (And obviously double the dose). Thanks!

 

[carrico]

So just to clarify - are you suggesting to dose every other hour instead of every hour? (And obviously double the dose). Thanks!

Exactly Patrick. At the moment I'm using TM's Carbocalcium, so I'm just dosing this element for alk and Ca, so I divided it into 12 dosages (every other hour). But when I was doing 2 part dosing, I divided into 12 dosages each element, with a difference of 1 hour for each one. That's what I was able to maintain in a more stable way during the period of light on and off.

 

[Patrick Cox]

Exactly Patrick. At the moment I'm using TM's Carbocalcium, so I'm just dosing this element for alk and Ca, so I divided it into 12 dosages (every other hour). But when I was doing 2 part dosing, I divided into 12 dosages each element, with a difference of 1 hour for each one. That's what I was able to maintain in a more stable way during the period of light on and off.

That's interesting. I wonder why that works. I could understand more during the day and less at night. I may give that a try. I'll let you know. Thanks.

 

[Diverdown1]

The swing overnight is normal. as long as you test consistent times and get the same reading, nothing to worry about.

 

[Patrick Cox]

The swing overnight is normal. as long as you test consistent times and get the same reading, nothing to worry about.

Thanks! [emoji1303]