Alk and nutrients

[top shelf]

So I know there is a correlation between nutrients and alkalinity. If you have low nutrients you want a lower alk, if you have higher nutrients higher alk.

My tank has always tested at P-.03 and N .2, my alk is fairly stable at 8.3 it drifts no more then +/- .5 a day with the addition of kent Tech B in the am. I have some zoas, GSP, torch, hammer, blasto, and a single Monti cap. Everything is looking good and healthy. My zoa growth is rather slow but I accept it's because of the low nutrients. The lps with the exception of my blasto are growing and doing well. The blasto just hasn't been happy no matter where I put it. I swear I can see my Monti grow by the day. What I am wondering is if I would see any benefit in droping my alk from 8.3 to maybe 8.0 or even 7.9.

Looking for people's thoughts and opinions.

 

[Bpb]

I don't believe lowering alkalinity will positively effect the zoas. It's been postulated that zoas are especially more sensitive to trace elements than even acropora. Perhaps increasing your water change regiment or an icp test would help


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[top shelf]

Something I forgot to add was I am looking to begin adding more sps's to the system. I like my zoas and all but I'm ok if they stay the way they are. Sps is what brings me to wonder if lowering will be beneficial. I want to have my water right before I start adding more. My Monti is doing well so next I would like to add maybe a birdsnest and a stag to see how well they do, then move on to some cheaper acro. Maybe I'm getting to far ahead of myself and should just adjust as I add more.

Its a 45g system total volume and I change 10% every Saturday because it's fast, easy, and convenient to to it with 5g buckets. Part of why I do it so often.

 

[Bpb]

In that case yes lowering would be beneficial


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[top shelf]

In that case yes lowering would be beneficial


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Thanks, I just wasnt sure if my alk was low enough for my nutrient levels and going forward with sps.

So if both N and P stay where they are what would be a good range to aim for 7.9 or lower?

 

[bertoni]

Alkalinity at 8.3 dKH is fine, and dropping it is very unlikely to help stony corals. People who have problems with higher alkalinity levels generally are dosing organic carbon (vodka, etc) and have alkalinity at the 10 dKH level or so. If you're very worried, letting the alkalinity drop slowly to 7.5 or so would be safe. Higher alkalinity generally encourages more growth, strangely, so it's not clear what's happening with carbon dosing or very low nutrients.

 

[top shelf]

Alkalinity at 8.3 dKH is fine, and dropping it is very unlikely to help stony corals. People who have problems with higher alkalinity levels generally are dosing organic carbon (vodka, etc) and have alkalinity at the 10 dKH level or so. If you're very worried, letting the alkalinity drop slowly to 7.5 or so would be safe. Higher alkalinity generally encourages more growth, strangely, so it's not clear what's happening with carbon dosing or very low nutrients.

I have read a lot of the back and forth on alk and nutrient levels and thought maybe it would be worth a shot to try and lower it a little since my nutrients are low. I've always focused on stability because numbers don't matter if you can't keep it stable. Personally I've never carbon dosed and don't see a need to but I did notice that as well.

 

[Tripod1404]

I have my N at 2.5 ppm, P at 0.01-0.03 ppm and alk at 7.5-7.3 dKH. I dont dose carbon but my system tends to deplete nutrients pretty effectivly. I need to dose nitrate to keep it at that value and feed heavy few times per week prevent P going zero (if I miss or skip these feedings, it goes to zero). I also dont have GFO or other types of P absorbing media. I do have a fuge but I greatly reduce photo period to 6 hours a day ,which helped with reducing N consumption.

I tried keeping alk at ~8.3-8.5 dKH, but it was causing my SPS to be overly sensitive and pale. At that alk,changing bulbs always caused them to get burned on the tips and some branches occasionally STNed without any apparent reason. I wasnt able tto keep montis high in the tank as well, they always bleached and died. Since lowering alk they got their color back and they no longer sensitive to light or other changes. I can now keep montis high as well.

 

[bertoni]

I agree that lowering the dKH a bit is safe, and there's no reason not to try it. Having problems at dKH 8.3-8.5 is on the low end of the reports I've read, but might be possible. The usual symptoms are dead tips, though, not slow growth.

 

[top shelf]

I have my N at 2.5 ppm, P at 0.01-0.03 ppm and alk at 7.5-7.3 dKH. I dont dose carbon but my system tends to deplete nutrients pretty effectivly. I need to dose nitrate to keep it at that value and feed heavy few times per week prevent P going zero (if I miss or skip these feedings, it goes to zero). I also dont have GFO or other types of P absorbing media. I do have a fuge but I greatly reduce photo period to 6 hours a day ,which helped with reducing N consumption.

I tried keeping alk at ~8.3-8.5 dKH, but it was causing my SPS to be overly sensitive and pale. At that alk,changing bulbs always caused them to get burned on the tips and some branches occasionally STNed without any apparent reason. I wasnt able tto keep montis high in the tank as well, they always bleached and died. Since lowering alk they got their color back and they no longer sensitive to light or other changes. I can now keep montis high as well.

My system doesn't deplet it quickly they just kinda stay the same with very minimal fluctuation. I have started feeding daily now instead of every other day to see how that does. I recall a thread where you mentioned reducing your sump photoperiod so as of 2 days ago I dropped mine from 12 to 10 hrs. My Monti is about halfway up and has great growth but color isn't as good as it could be maybe lowering alk could help.

 

[top shelf]

I agree that lowering the dKH a bit is safe, and there's no reason not to try it. Having problems at dKH 8.3-8.5 is on the low end of the reports I've read, but might be possible. The usual symptoms are dead tips, though, not slow growth.

All my numbers are very close to that of nsw with the exception being alk. I'm going to slowly lower it to 7.9 and see how that goes.

 

[bitwise]

I’m not an expert but I doubt lowering alk is going to improve zoa growth. For me, when I had zoas, it’s just been about time. Also, I think that zoas and palys need an encouraging surface to grow into. Once my frags completely covered their plug they would stop expanding (I had the plugs on a bare bottom).

 

[top shelf]

I'm not an expert but I doubt lowering alk is going to improve zoa growth. For me, when I had zoas, it's just been about time. Also, I think that zoas and palys need an encouraging surface to grow into. Once my frags completely covered their plug they would stop expanding (I had the plugs on a bare bottom).

I'm not to worried about the zoas, if they grow they grow if they don't that's ok too. I'm looking to go in the direction of sps which the correlation relates more to. I may add a Duncan, acan, and atleast one more torch since I really want a gold Aussie but the tank will be predominantly sps.

 

[Tripod1404]

All my numbers are very close to that of nsw with the exception being alk. I'm going to slowly lower it to 7.9 and see how that goes.

I determined my ideal alk number by determining the alk value that gave me maximum daily alk consumption. When my alk is at ~7.4dKH, my doser needs to add ~1.5dKH equivalents of alk solution. So my alk consumption rate at 7.4dKH is 1.5dKH per day. When I did the same thing at 8.5 dKH, my alk consumption is around ~0.8dKH. THis showed my my corals were happier and grew faster at 7.4 dKH compared to 8.5dKH.

Every tank is different, what worked for me might not work for you even if we have the exact same parameters. Things like light, flow, temperature, dissolved organics, etc. also greatly influence health of SPS coral. Those things are very difficult to replicate between tanks. So best thing you you can do determine at which alk, your corals consume it the most. This will show you your ideal alk level for the given nutrient levels.

 

[top shelf]

I determined my ideal alk number by determining the alk value that gave me maximum daily alk consumption. When my alk is at ~7.4dKH, my doser needs to add ~1.5dKH equivalents of alk solution. So my alk consumption rate at 7.4dKH is 1.5dKH per day. When I did the same thing at 8.5 dKH, my alk consumption is around ~0.8dKH. THis showed my my corals were happier and grew faster at 7.4 dKH compared to 8.5dKH.

Every tank is different, what worked for me might not work for you even if we have the exact same parameters. Things like light, flow, temperature, dissolved organics, etc. also greatly influence health of SPS coral. Those things are very difficult to replicate between tanks. So best thing you you can do determine at which alk, your corals consume it the most. This will show you your ideal alk level for the given nutrient levels.

I honestly never even thought about that. I completely agree no 2 tanks are ever the same even if you try to replicate and do everything the same. I know at current my consumption rate is low at about .2 dkh a day and has been that way for a few months now. So I have a good starting place atleast. After I slowly lower and stabilize it at 7.9 I will test for a month and see if it increases or decreases.

 

[bitwise]

That’s a smart idea for finding the optimal concentration of alk. I’d be weary of all the other variables though. I might give that a shot. I basically started my tank, alk was around 8.5, and I set it there for good. I haven’t experimented at all.

 

[top shelf]

There is a lot of variables tank to tank that one needs to account for but every tank will still have a optimal level for alk use and I agree that it's a great idea. You learn something new everyday and it's one of the things I love about this site and part of why I asked.

My tank has been up for almost 9 months now and stabile so I feel confident about tweeking little things here and there to see if I can make some improvements.

I tested my alk last night, even though it was a few hrs after lights out which I prefer to test when they're on for a more accurate reading. I felt it would still be close enough and got a reading of 7.9. That morning I only added 2ml instead of 3 so being less than a .5 drop I'm not too worried. Now just going to monitor over the next month and see how things go.