Alk

[Rainblood]

I've been fiddling with dosing alk recently and it seems my 50g frag tank is dropping about ~.5dkh daily.
Its got about 20ish acro frags and a 6in derasa. Does that sound right?

I honestly don't have any points of reference but dosing 16mL alk daily just seems like a lot?

Whats your guys's (I hate the word y'all) consumption look like and how much are you dosing?

 

[dball711]

I have a 60g frag tank mostly acros using 44ml of ALK from the Bionic System daily to keep my ALK stable at 8DKH.

 

[timeconsumer]

A 75g I used to have which was all LPS, softies, and one big ol deresa took about 50ml a day of soda ash 2 part.

For what it's worth a 0.5 DKH consumption is going to be roughly 2 or 3ppm consumption in calcium per day as well. Sometimes it can seem counter-intuitive that alkalinity drops by 10% and calcium only drops by 0.5% but that is what an even consumption of the two of them looks like.

 

[Rainblood]

Ok wow. I didn't realize how much Alk these tanks suck up.
I haven't really been too worried about calcium but should probably start measuring that as well.

 

[Rainblood]

So I've been manually monitoring and dosing...and it seems like Alk consumption doesn't really stay steady.
Does it ever stabilize over time or will it continually fluctuate? Thanks

 

[jcook54]

In my experience, it can fluctuate, to a point. I test for Alk once a week since I have any auto doser that keeps things pretty steady. Occasionally I have to add a mL or two per day to keep things in line as things grow. However, if Alk starts creeping (or shooting) up, that is usually a sign that something is wrong. I keep my Alk around 8.0 dKh and in early February I tested it at 9.6 dKh when the week before was 8.0. I dropped the dose but something was wrong with the tank and I'm still dealing with the chalices that are not at all happy. I don't know exactly what the cause is but the first sign that something was wrong could be found in a shut down of coral growth evidenced by the Alk increase.

I believe that what we see in our systems with our eyeballs is actually an indication of how happy things were a few weeks ago. Some problems get an immediate response but a lot of time things happen slowly. I use Alk consumption as early indicator for how the tank will be looking in the near future. Right now my frag tank does not look great BUT my Alk consumption is slowly stabilizing and even going up some. I expect that the corals that aren't happy right now will look a lot better come May.

 

[hzheng33]

i lose about 1dkh a day if i turn off my cal reactor.

 

[timeconsumer]

In my experience, it can fluctuate, to a point. I test for Alk once a week since I have any auto doser that keeps things pretty steady. Occasionally I have to add a mL or two per day to keep things in line as things grow. However, if Alk starts creeping (or shooting) up, that is usually a sign that something is wrong. I keep my Alk around 8.0 dKh and in early February I tested it at 9.6 dKh when the week before was 8.0. I dropped the dose but something was wrong with the tank and I'm still dealing with the chalices that are not at all happy. I don't know exactly what the cause is but the first sign that something was wrong could be found in a shut down of coral growth evidenced by the Alk increase.

I believe that what we see in our systems with our eyeballs is actually an indication of how happy things were a few weeks ago. Some problems get an immediate response but a lot of time things happen slowly. I use Alk consumption as early indicator for how the tank will be looking in the near future. Right now my frag tank does not look great BUT my Alk consumption is slowly stabilizing and even going up some. I expect that the corals that aren't happy right now will look a lot better come May.

Exactly how it happens with me too. I had an incident recently where my tank that normally drops about 1dkh per day completely stalled out on growth because my lights accidentally were on for about 48 hours straight and everything got angry. As the weeks go by and everything recovered I can see alk consumption climbing right back to where it was.

Also another thing to consider is that your alk will also get consumed by nitrifying bacteria consuming ammonia. During the conversion of NH3 to NO2 and eventually NO3 you are left with an extra H+ floating around which can bond with your bicarbonate to form carbonic acid which will eventually leave the system as CO2 gas.