Trying to reduce alkalinity, but the less I dose, the higher my alk goes?

[Fishdisease]

Hey Everyone

Here are my tank stats as of this morning, System size is 400 gallons, mixed reef

Alk: 12.0
Cal: 420
Mag 1100
Temp: 78
pH: 8.12
Nitrate: >2
Phosphate: >0.01
Salinity: 1.025

I dose cal/alk via BRS Dosers and a timer, manually test both parameters daily.

I'd like to get my alk down to 9-9.5 as I have a mixed reef and my LPS aren't really flourishing in the high alk. Last week my dosing schedule was 528ml (5.5 ml every 15 minutes) of Randy's Recipe 2 daily and my alk was 11.5. I reduced my dosing to 480ml per day 7 day ago and since I've done that I've been seeing the alk creep up over that week to 12 dkh. What on earth could be happening? What am I missing here? Does it have anything to the calcium/alk balance?

 

[Ippyroy]

The calcium alk balance at Alk being 9Dkh has calcium being at 421, so that is not the issue. What are you testing with? Have you made sure the test kit is not expired? Have you had a LFS check it for you?

 

[Biglew11]

plus one on making sure test is accurate. also you can stop dosing alk and let it drop to your desired levels. then slowly ramp dosing back up to the point alk remains stable.

 

[Fishdisease]

The calcium alk balance at Alk being 9Dkh has calcium being at 421, so that is not the issue. What are you testing with? Have you made sure the test kit is not expired? Have you had a LFS check it for you?

All my kits are Rea Sea Pro kits and the alk was just purchased/opened 2 weeks ago. I actually bought a new test kit specifically for this project. I have double checked it against the old kit and the red sea standard alk test kit.

lol, as for my LFS, last time I took water in there to test I ended up teaching the associate how to test the water. But there is a new guy working that seems far more competent, lol. I'll try it again.

 

[Ippyroy]

All my kits are Rea Sea Pro kits and the alk was just purchased/opened 2 weeks ago. I actually bought a new test kit specifically for this project. I have double checked it against the old kit and the red sea standard alk test kit.

lol, as for my LFS, last time I took water in there to test I ended up teaching the associate how to test the water. But there is a new guy working that seems far more competent, lol. I'll try it again.

Sounds like it really is high. Personally I love the Hanna alk checker. 50 bucks to buy then only 9 for reagents. And on sale at a great price.

Alkalinity DKH Colorimeter HI772 Hanna Checker - Marine Water

Why does BRS recommend this? The Hanna Alkalinity checker is an awesome little tool that now will give results in DKH values that are much more common in the aquarium hobby. It will also give you accurate easy to read results with the large LCD display. We like the repeatable results and ability...

www.bulkreefsupply.com

 

[Fishdisease]

Sounds like it really is high. Personally I love the Hanna alk checker. 50 bucks to buy then only 9 for reagents. And on sale at a great price.

Alkalinity DKH Colorimeter HI772 Hanna Checker - Marine Water

Why does BRS recommend this? The Hanna Alkalinity checker is an awesome little tool that now will give results in DKH values that are much more common in the aquarium hobby. It will also give you accurate easy to read results with the large LCD display. We like the repeatable results and ability...

www.bulkreefsupply.com

Yes it is, that's why I'm trying to lower it slowly as to not stress out my corals.

I'm also quite happy with the RSP kits. I also replace my reagents before the old batch runs out so I can double check against the old ones and I've found they are very consistent. It's a moot point anyway as I'm ordering a Trident soon as my work will be picking up in the coming weeks and I travel a lot.

I'm more interested in if anyone could explain why the less I dose the higher my alk actually gets. Is the coralline on the glass dissolving as pH goes down causing that increase? What other things could there be?

 

[Biglew11]

if stuff that takes up alkalinity (coral, coraline, snails, etc.) decreases in growth rate then its possible that you are still dosing more than is needed. i think i'd try dropping my dose to about 50% of what it was and let it drop from there, then increase slowly until its stable again.

Here are my tank stats as of this morning, System size is 400 gallons, mixed reef

Alk: 12.0
Cal: 420
Mag 1100
Temp: 78
pH: 8.12
Nitrate: >2
Phosphate: >0.01
Salinity: 1.025

what are your nitrates and phosphates? they're detectable so that's good. what does nutrient food input export look like? if your feeding alot and nitrate, phosphates are that low them that's good, if your starving the tank and nutrients are barely detectable then things will start to suffer.
if stuff isn't getting enough nutrients they wont grow, possibly causing alkalinity to continue to increase.

 

[sagedrake690]

Chestnut wine tannins. I did an experiment. 1/4 tsp in 60 gal will make it yellow. This will chance ph to slightly more acidic only as long as it is in the water. It can be removed with carbon and drops alk by 1-2 a day.

 

[sagedrake690]

You can use 1/8th tsp to have a lesser effect. It seems dose dependant and the length of time you leave it in.

 

[X-37B]

Get your mag in range as its low and just dose ca until alk is in range.