Am I over thinking this precipitation thing?

[homer1475]

I’m dosing 260mL of each 2 part in my 260 gallon tank.

1.4DKH a day.

Again in the same boat as me, where a CalRx might be cheaper in the long run. Most certainly in your case. CalRx kind of fell out of popularity, but I think they are the only way to dose in a large tank.

 

[Miami Reef]

1.4DKH a day.

Again in the same boat as me, where a CalRx might be cheaper in the long run. Most certainly in your case. CalRx kind of fell out of popularity, but I think they are the only way to dose in a large tank.

But I really like 2 part. I like how simple it is and how I don’t have to mess with things like CO2 reactor etc.

Plus, I really like what 2 part (using NaOH) does to my pH. I can achieve a pH from 8.3 to 8.5 (night to day, respectively.)

I’m fortunate that ongoing cost for calcium doesn’t seem like much for me.

I will say, that my tank is low demand (mainly frags and small clams) but I do plan on using 5 gallon jugs and seeing if my solutions can be made slightly more concentrated in the future.


Who knows, I may decide to add a calcium reactor, or I might just do my current 3 part + kalkwasser in my ATO. I’ll take it as it comes.

 

[Rigoberto]

the thing is I used to be able to make small adjustments to my DKH with adding or taking away small amounts from my dosing. If I added 2ml or 4 ml then I would see like .2 or .4 increase in my DKH. Now over the past month I have increased my dosage 40% but the DKH sits at 7 not moving. Yes, you are correct on total volume 65 to 70g. I do have 2" sandbed. I cant see going from current 26ml all the way to 100ml that seems like a huge increase for my tank.

I experienced something similar recently. The soda ash I added seemed to be precipitating and kh kept dropping to ~7.x. Raising dosing rate seem to be creating an oscillation. So, I stopped dosing.

I cleaned out the precipitate in the vicinity of my dosing and added more flow to that area which is synchronized to the dosing.

I also made a "big" adjustment with Sodium Bicarbonate instead of Sodium Carbonate. Much more stable at 8.x-9.x now.... still dosing sodium carbonate, but at 1/2 the rate.

 

[Rigoberto]

True, I'm just concerned with 7 DKH. If I go a week between tests it may fall into unhealthy range. Secondly, why can't I get my DKH to increase?

What's your pH doing?

 

[Lavey29]

What's your pH doing?

I don't really monitor it. I run a fuge to balance PH overnight. I only test it periodically with cheap test strips.

 

[92Miata]

So, my tank had been running consistent around 8 to 8.4 DKH for over a year and over the past month I noticed that it dropped to 7 DKH. My full tank stock of corals are really flourishing so I just figured that it was normal consumption combined with all the coraline developing also. The tank seemed to like the 7 range so I started to slowly increase my alk dose to balance it at 7.5 which gives me a little buffer in case it drops again. over a period of time I noticed my alk level was not increasing. I have slowly been adding more to my daily dosage but the alk just sits at 7 (checked daily at the same time). I have increased 40% from 18ml to 26ml per day and it doesn't move. I started to focus on precipitation but did not see any of the obvious indicators. Sand is not hard or clumpy. I don't see calcium build up on my equipment. My magnesium is normal and dosed once per week currently at 1410 via ICP test. My calcium has not been rising even though I matched the dose increase to pair with the alk increase. Shows about 460 currently on hanna checker. My salinity stays at 1.026. I don't really test PH other then basic test strips which always show around 8.0 but I run a fuge overnight to balance PH and the office where the tank is located is fairly well ventilated with a fan and AC. I think I have precipitation going on but can't say for certain.

The caveat is that the tank is running perfect with significant SPS growth and color and also my LPS and softs are thriving. So, should I be concerned at all or just let the tank to do its thing and not chase numbers at all? I do water changes of 15% every 3 weeks with coral pro salt. This situation is perplexing to me though which is why I like to defer to the brain trust here for advice...thanks in advance for your suggestions.

So leave it alone.

Double check your magnesium to make sure that's not causing issues with the alk dosing - but beyond that just let it be. There are a TON of sps keepers running 6-7 dkh. It's absolutely fine.

You get marginally faster growth at higher dkh if everything is perfect, but if not, you get way more stress events, and way slower growth. Things are way easier alkalinity closer to NSW.

 

[Lavey29]

So leave it alone.

Double check your magnesium to make sure that's not causing issues with the alk dosing - but beyond that just let it be. There are a TON of sps keepers running 6-7 dkh. It's absolutely fine.

You get marginally faster growth at higher dkh if everything is perfect, but if not, you get way more stress events, and way slower growth. Things are way easier alkalinity closer to NSW.

I don't have a problem letting the tank run at those alk levels but my concern was that I was getting precipitation because I could not get alk to move up at all. I now know that is a false situation. My magnesium is 1410 via ICP test.