Alk drops even after testing for daily usage and adding 2 part

[kaceyo]

Hey guys, My alk keeps dropping even after I calculated the daily/weekly usage and added the appropriate amount of 2/3 part. I use Red Sea foundation additives and red sea test kits. My tank is 40g with 20 cal using frags from small .5" to 1" and a few 3" to 4" sticks. I wouldn't expect to have to use 2 part yet but tests seemed to show that I need to. I have very heavy coraline growth, with it completely covering the bottom (bare bottom) anywhere light hits. The tank is 6+ mo old.
Right now I'm adding 7ml alk and 4ml cal p/d. I started with 1 ml each alk and cal a few mo back and it has slowly climbed as my alk kept dropping. I always added equal amounts of each until my cal rose to over 500ppm while alk slowly dropped. It started at 10 dkh and is now in the mid to high 7's. Im using standard IO salt which tests at 10dkh freshly maid and raises my dkh by 0.2dkh right after a w/c. I do weekly 15% w/c's w/out fail.
Any advice you can give will be greatly appreciated and I really need to know what steps to take to get a handle on this. I'm using way too much alk supplement, or I think I am, and figure it must be precipitating out but don't know how to fix it.
Thanks, Kacey

 

[Smite]

You are dosing the two at seperate times correct? Letting water clear from alk then dosing cal?

What is your magnesium level at? Sometimes if your mag level is too low, or very out of balance with you calcium level, it can be hard to maintain an alk level.

I try to keep my magnesium roughly 3x the level of my calcium. So for your 500ppm calcium level shoot for 1500ppm magnesium.

I have never had that equal parts dosing work out for me. My calcium is usually much higher than my alkalinity. Even with a calcium reactor i end up dosing calcium here and there.

 

[kaceyo]

You are dosing the two at seperate times correct? Letting water clear from alk then dosing cal?

What is your magnesium level at? Sometimes if your mag level is too low, or very out of balance with you calcium level, it can be hard to maintain an alk level.

I try to keep my magnesium roughly 3x the level of my calcium. So for your 500ppm calcium level shoot for 1500ppm magnesium.

I have never had that equal parts dosing work out for me. My calcium is usually much higher than my alkalinity. Even with a calcium reactor i end up dosing calcium here and there.

Hey Smite, the mag started out at 1400ppm months ago and slowly dropped to 1280 last month. I dosed it back up to 1350 and will monitor it. I figured that 1280 was within acceptable range so haven't worried about it. I always wait at least 10 mins between dosing alk and cal, and dose alk 1st.

 

[ambientaquatics.adam]

I lose about .5 -.7 dkh daily. Coraline algae is an alk vaccum.

 

[kaceyo]

I lose about .5 -.7 dkh daily. Coraline algae is an alk vaccum.

I thought my coraline algae could be pulling alot more cal out of the water than my coral, but I should still be able to reach a point where I'm adding enough to equal that amount.

 

[ambientaquatics.adam]

http://reef.diesyst.com/cf/chemcalccf.html

Here's how I found my range, I dosed up to 9 dkh I waited three days without dosing and tested. Took the difference and divided it by three. Then using that calculator you can see what you need to dose daily. I do this test when I start seeing my alk checker results trending down to "recalibrate" my alk dosing.

 

[kaceyo]

http://reef.diesyst.com/cf/chemcalccf.html

Here's how I found my range, I dosed up to 9 dkh I waited three days without dosing and tested. Took the difference and divided it by three. Then using that calculator you can see what you need to dose daily. I do this test when I start seeing my alk checker results trending down to "recalibrate" my alk dosing.

That's exactly what I did when I started this process, except I waited 4 days. Same thing though. But the recommended daily dosage never brought the alk back up to the original starting point. It crept downwards and I slowly added a bit more 2 part, never getting back to that original #. I've read that you shouldn't chase #'s. but would just like to be able to hit that original starting point. And now I'm adding enough to make me worry that it's having detrimental effects on my livestock.

 

[Randy Holmes-Farley]

Hey guys, My alk keeps dropping even after I calculated the daily/weekly usage and added the appropriate amount of 2/3 part. I use Red Sea foundation additives and red sea test kits. My tank is 40g with 20 cal using frags from small .5" to 1" and a few 3" to 4" sticks. I wouldn't expect to have to use 2 part yet but tests seemed to show that I need to. I have very heavy coraline growth, with it completely covering the bottom (bare bottom) anywhere light hits. The tank is 6+ mo old.
Right now I'm adding 7ml alk and 4ml cal p/d. I started with 1 ml each alk and cal a few mo back and it has slowly climbed as my alk kept dropping. I always added equal amounts of each until my cal rose to over 500ppm while alk slowly dropped. It started at 10 dkh and is now in the mid to high 7's. Im using standard IO salt which tests at 10dkh freshly maid and raises my dkh by 0.2dkh right after a w/c. I do weekly 15% w/c's w/out fail.
Any advice you can give will be greatly appreciated and I really need to know what steps to take to get a handle on this. I'm using way too much alk supplement, or I think I am, and figure it must be precipitating out but don't know how to fix it.
Thanks, Kacey

Alk demand rises as the actual alk rises. It is far higher at 10 dKH than at 6 dKH. That's a drawback of determining the daily demand in any way except trial and error dosing.

If you total alk you are dosing daily is not out of line with typical tanks, then just dose more.

 

[ckalupa]

Also check out your sand bed- if it is starting to turn hard you know where some of the alk is ending up.

 

[Dkeller_nc]

It's not unusual to see alk demand a bit higher than calcium on a molar ratio. One reason is that the nitrate cycle "uses" alkalinity. That's for oxidation of ammonia through to nitrate. You recover the alkalinity consumed if the nitrate is reduced by bacteria to nitrogen gas, but it's not unusual for a relatively newish tank to not have much of a nitrate reduction aspect.

 

[kaceyo]

Alk demand rises as the actual alk rises. It is far higher at 10 dKH than at 6 dKH. That's a drawback of determining the daily demand in any way except trial and error dosing.

If you total alk you are dosing daily is not out of line with typical tanks, then just dose more.

Hi Randy, That's one of the things that concern me most. Isn't 7mls p/d (of Red Sea Alk ) being unable to keep up with a 6 mo old tank with just 20 small alk consuming frags (and lots of coraline algea) out of line with a typical tanks demand? From what I've read I probably shouldn't even need to dose yet and wc's should be enough.

 

[kaceyo]

Also check out your sand bed- if it is starting to turn hard you know where some of the alk is ending up.

It's a bare bottom that's about 80% covered in coraline algea. It really took off in my tank.

 

[kaceyo]

It's not unusual to see alk demand a bit higher than calcium on a molar ratio. One reason is that the nitrate cycle "uses" alkalinity. That's for oxidation of ammonia through to nitrate. You recover the alkalinity consumed if the nitrate is reduced by bacteria to nitrogen gas, but it's not unusual for a relatively newish tank to not have much of a nitrate reduction aspect.

I had about 20 ppm nitrate which convinced me to cut way back on my feeding (I only have 3 small fish anyways) and increase wc's to once a week 15% and that dropped it down to under 5ppm within a few weeks.

 

[kaceyo]

I want to say thanks to all those who are chipping in here. With help I know I will figure this alk thing out but the chemical processes are a bit over my head. I just need some practical advice and tips,
Thanks again,

Kacey

 

[Randy Holmes-Farley]

Hi Randy, That's one of the things that concern me most. Isn't 7mls p/d (of Red Sea Alk ) being unable to keep up with a 6 mo old tank with just 20 small alk consuming frags (and lots of coraline algea) out of line with a typical tanks demand? From what I've read I probably shouldn't even need to dose yet and wc's should be enough.

Can you calculate the dKH dosed per day?

 

[kaceyo]

Can you calculate the dKH dosed per day?

According to the bottle 1 ml/25gal = 0.1 dkh increase. so 7 ml into 40gls is just... under .52dkh? I have no idea if this is right but tried to do it w/out a reef calculat0r, lol. Am I even close?

 

[Dkeller_nc]

You're close, though the exact calculation would be 7 mL/day * 0.1 (dKH/gal mL) * (25 gal / 40 gal) = 0.44 dKH/day. That's not an unusually high demand for a tank with actively growing corals and/or coralline algae. One thing you don't say in the thread, unless I've missed it, is the constant alkalinity level in your tank that you're shooting for. You did mention that you started at 10 dKH, and the tank's hovering around 7 dKH at present, but that's not exactly a target. Most SPS keepers nowadays tend to have a target alkalinity around 8 dKH, with some targeting higher than that if they also have relatively high nutrients.

However, high alkalinity, strong light, and low nutrients is not a good thing. Given that you have a relatively new tank, I would suggest just continuing to do what you're doing and keep your level at about where it is (7 dKH). Your corals might not grow quite as fast as they would at slightly higher alkalinity, but it's better to be somewhat low with a new, low nutrient tank than high.

 

[kaceyo]

You're close, though the exact calculation would be 7 mL/day * 0.1 (dKH/gal mL) * (25 gal / 40 gal) = 0.44 dKH/day. That's not an unusually high demand for a tank with actively growing corals and/or coralline algae. One thing you don't say in the thread, unless I've missed it, is the constant alkalinity level in your tank that you're shooting for. You did mention that you started at 10 dKH, and the tank's hovering around 7 dKH at present, but that's not exactly a target. Most SPS keepers nowadays tend to have a target alkalinity around 8 dKH, with some targeting higher than that if they also have relatively high nutrients.

However, high alkalinity, strong light, and low nutrients is not a good thing. Given that you have a relatively new tank, I would suggest just continuing to do what you're doing and keep your level at about where it is (7 dKH). Your corals might not grow quite as fast as they would at slightly higher alkalinity, but it's better to be somewhat low with a new, low nutrient tank than high.

Hey Dkeller, I didn't post a target dkh because I was more concerned about what seemed to me to be a never ending drop in alk while I was increasing the dosage in a tank I had read shouldn't have much of a need for dosing at all yet, especially with weekly 15% wc's. I'd thought that a dkh of 8.5 would be a good target to shoot for once I get the dosing down and can control it better. I was planning on using sodium bicarbonate along with the 2part daily dosage to slowly bring the alk up to 8.5 and then continue with the red sea 2 part to keep it stable there. Does that sound like a reasonable plan and goal or would sticking with 7dkh be better?

 

[kaceyo]

Another quick Q. With my cal over 500 and alk in the 7's is it ok to dose alk only for a while and let cal drop back into a more reasonable range, say about 450ppm cal? Or should I keep dosing cal along with the alk, and if so, how much calcium?

 

[Dkeller_nc]

Another quick Q. With my cal over 500 and alk in the 7's is it ok to dose alk only for a while and let cal drop back into a more reasonable range, say about 450ppm cal? Or should I keep dosing cal along with the alk, and if so, how much calcium?

Yes, that's precisely what you should do - just dose alk, and continue to monitor the calcium levels until they reach 400 - 450 ppm. Opinions will vary on where to maintain this parameter, but the takeaway is that it doesn't matter all that much as long as it's not really low (<380ppm) or really high (>450 ppm).

Targeting 8.5 dKH for alkalinity is reasonable, but the main reason I suggested just maintaining at the level you're at for a while is to gain some experience about how much your tank uses, allow the Ca level to correct itself, and to slowly increase the alk - absolute max of 0.5 dKH per day. Alkalinity stability is at least as important as the absolute level.