Am I over thinking this precipitation thing?

[Lavey29]

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.

 

[homer1475]

Do you know what your daily consumption is?

Also what size tank are we talking here? Depending on tank size 26ml isn't much alk.

For example I dose 104ml(roughly 1.7dkh) to an 85G sps dominate system daily.

 

[homer1475]

You also did not mention what your using for ALK?

 

[Lavey29]

Do you know what your daily consumption is?

Also what size tank are we talking here? Depending on tank size 26ml isn't much alk.

For example I dose 104ml(roughly 1.7dkh) to an 85G sps dominate system daily.

tank is 65g DT with 15g sump. I have not really kept current track of daily consumption because for multiple months now the tank has been table at my dosage level of 18ml per day which maintained consistent 8 to 8.4. It has just been the past month that I noticed the drop to 7 DKH which obviously indicates more consumption which is normal with coral and coraline growth. I started doing 2ml increases and would check the level daily for like 3 days. When I saw no movement on the alk I would add another 2ml and check again and so on.

 

[Lavey29]

You also did not mention what your using for ALK?

2 part bionic

 

[homer1475]

Ok do it this way to get a baseline then.

I'm going to assume your around 7DKH. Lets bump that up to 7.8(still on the safe side for 1 bolus dose(shouldn't go over 1DKH in 24 hours as a bolus dose), but gives us some wiggle room).

Use a calculator to get your dosage:

Reef Chemistry Calculator

With displacement(do you have sand?), I'm guessing around 65G total with sump and rock and sand.

100.3ML. I would dose 100, and test again to get a baseline(playing with the calc, you can also figure out your exact gallons).

Do not add anything for 2 days, and test each day at the same time. This will get you your daily consumption(how much does it drop each day?), then you using the calc, you can figure out how much you should be dosing daily.

FWIW:
Using that calc, and your original post, you only dosing 0.2DKH of alk. Which is not much at all(assuming you have roughly 65G system volume).

 

[Lavey29]

Ok do it this way to get a baseline then.

I'm going to assume your around 7DKH. Lets bump that up to 7.8(still on the safe side for 1 bolus dose(shouldn't go over 1DKH in 24 hours as a bolus dose), but gives us some wiggle room).

Use a calculator to get your dosage:

Reef Chemistry Calculator

With displacement(do you have sand?), I'm guessing around 65G total with sump and rock and sand.

100.3ML. I would dose 100, and test again to get a baseline(playing with the calc, you can also figure out your exact gallons).

Do not add anything for 2 days, and test each day at the same time. This will get you your daily consumption(how much does it drop each day?), then you using the calc, you can figure out how much you should be dosing daily.

FWIW:
Using that calc, and your original post, you only dosing 0.2DKH of alk. Which is not much at all(assuming you have roughly 65G system volume).

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.

 

[homer1475]

The calculator does not lie. Trust it. I've used it for many, many years.

If you don't trust the 100ml, then go half, and test, only way you'll know for sure.


Again, assuming the calculator is correct(never not had it be for any supplement, and even Randy tells everyone to use it), your dosage of 26ml is only 0.2DKH. Dose your 26ml is one bolus dose, wait 10 minutes and test. See what the result is. Just keep in mind even test kits have a small margin of error so I wouldn't count on specific numbers, but should be in the ballpark.

 

[Lavey29]

The calculator does not lie. Trust it. I've used it for many, many years.

If you don't trust the 100ml, then go half, and test, only way you'll know for sure.


Again, assuming the calculator is correct(never not had it be for any supplement, and even Randy tells everyone to use it), your dosage of 26ml is only 0.2DKH. Dose your 26ml is one bolus dose, wait 10 minutes and test. See what the result is. Just keep in mind even test kits have a small margin of error so I wouldn't count on specific numbers, but should be in the ballpark.

but isn't certain brands of alk more concentrated or less? how does the calculator adjust for that? I would probably feel better just doing like 5 or 10ml daily increases and just checking the alk number everyday again for a week or two.

How do I know I'm not getting precipitation?

 

[homer1475]

You said yourself your not seeing any classic signs of it. Hardening of sand, white crust on heaters, and inside pumps, white crust on the tank walls, all classic signs of precip.

Pic of tank and coral load would help here too.


Not sure how the calc works, and figures in the dosage for each product, but it does work, and has been around for many years.

 

[Lavey29]

You said yourself your not seeing any classic signs of it. Hardening of sand, white crust on heaters, and inside pumps, white crust on the tank walls, all classic signs of precip.

Pic of tank and coral load would help here too.


Not sure how the calc works, and figures in the dosage for each product, but it does work, and has been around for many years.

well I do see some white crust on my sump wall but it is right where the dosing head sprays down so I thought it was just residual splash from the dosing there but my heater right below it is clean.

 

[homer1475]

With that coral load, your not dosing much. That tanks pretty packed. I see quite a few growing sticks, and some pretty large LPS.

My tanks probably not half that full, although I have more SPS, but you see I dose 1.7DKH a day or 105ml of randys DIY 2 part(soda ash).

I think you just need to dose more.

Yes I have a small buildup on my sump wall right where I dose too. Nothing of concern though. If your heater right under the dosing line doesn't have a crust on it, your not loosing it.

 

[Lavey29]

With that coral load, your not dosing much. That tanks pretty packed. I see quite a few growing sticks, and some pretty large LPS.

My tanks probably not half that full, although I have more SPS, but you see I dose 1.7DKH a day or 105ml of randys DIY 2 part(soda ash).

I think you just need to dose more.

Yes I have a small buildup on my sump wall right where I dose too. Nothing of concern though. If your heater right under the dosing line doesn't have a crust on it, your not loosing it.

thank you for your advice. I am going to start a steady pattern of dosage increase day to day until I start to see movement in the DKH again. I would like to maintain 7.5 to 7.8 and currently 7 now still.

 

[KrisReef]

I have had this happen with an aging Hanna Checker Alk reagent providing unreliable results. I think my alk was 8 almost 9 when I figured out the source of error.

 

[Lavey29]

With that coral load, your not dosing much. That tanks pretty packed. I see quite a few growing sticks, and some pretty large LPS.

My tanks probably not half that full, although I have more SPS, but you see I dose 1.7DKH a day or 105ml of randys DIY 2 part(soda ash).

I think you just need to dose more.

Yes I have a small buildup on my sump wall right where I dose too. Nothing of concern though. If your heater right under the dosing line doesn't have a crust on it, your not loosing it.

So I thought since it was going below 7 that I had found the equilibrium point but I guess every small increase I add is just being consumed and my tank is stopping its consumption as the DKH hits 7?

 

[Lavey29]

I have had this happen with an aging Hanna Checker Alk reagent providing unreliable results. I think my alk was 8 almost 9 when I figured out the source of error.

How would I know? It's brand new package of liquid reagent.

 

[homer1475]

How would I know? It's brand new package of liquid reagent.

I would agree, that it could be the reagent.

Before chasing this, have you got another reagent bottle, or another test to confirm the hanna number?

 

[Lavey29]

I would agree, that it could be the reagent.

Before chasing this, have you got another reagent bottle, or another test to confirm the hanna number?

I will have one today for sure

 

[homer1475]

To rule out the reagent, you could also dose, wait 10 minutes, and test. You should get some sort of rise.

 

[Lavey29]

I would agree, that it could be the reagent.

Before chasing this, have you got another reagent bottle, or another test to confirm the hanna number?

ok just tried brand new reagent with expiration date of 6/23. I got a reading of 7.1DKH so virtually the same although its 3.5 hours before my normal test time today.