Ideal Alk level relative to nitrates (nutrients)

[Lovefish77]

Hi everyone,
I am trying to figure out the ideal level of nitrates (and nutrients in general) vs alk in my reef tank that is ideal for sps and acropora.
So basically like a grid;
-for 1-3ppm nitrates > alk of say 8 to 8.5
-for less than 1ppm nitrates > alk of 7.5 to 8

I have few sps and a few acros including big acro colony ; the acro is starting to have a hair of brown buildup on the tips that were growing and have perfectly white tips a few days ago. Another tell tale sign is another acro that is has been turning a bit whitish at the tip (pics to follow).
I know there are some rules"
- like never let your alk go above 8 if you run a very low nutrient system with zero nitrates or so.
- the higher the light the higher the nutrients you need to have in the tank

So my tank is heavily loaded and i was never able to register any nitrates that is why i keep alk below 8. Over the past few weeks i have been adding a soap of acro power and red sea AB+ like 4 mm in total daily. In addition to that i add some reef roids daily. After all that effort i was able to bump nitrates to 1 ppm.
Latest tests today:
Nitrates 1 ppm (salifert)
Alk (7.8-8dkh) (using Salifert as well)
I run high lights (reefbreeders) and the big acro colony has been sitting at like 380-400 par (of course acclimated gradually to that level).

Any thoughts or ideas?
Thanks a lot

 

[Lovefish77]

Some pics of small acro and colony I am concerned about

 

[Lovefish77]

Anyone?

 

[EagleEye121]

I’m of no help but interested to hear people’s thoughts. Following

 

[Lovefish77]

I’m of no help but interested to hear people’s thoughts. Following

Waiting anxiously for that secret formula as I like that colony I have

 

[Charlie’s Frags]

What’s your po4?
What are you doing for nutrient export?

 

[Reefahholic]

I had this same issue one time. After scratching my head for days we finally figured out it was a trace element overdose. Just something to think about.

If you haven't been dosing trace elements I'd start thinking about your lighting. LED's put out a ton of light. Bumping the lights down slowly could be an option. Of course observing the corals closely. You may have ticked off that big colony.

Take a look at the corals. Are they pale or do they have rich color? If rich color.... I wouldn't do anything to the N&P. If pale....I'd keep trying to raise the NO3. If the PO4 is low I'd try to raise that a little too. If you can't do it by feeding...it may be time to start dosing it back to the system.

In the meantime if you know the numbers are likely low one thing you can do right now is start skimming super dry or pull the skimmer cup off and let it overflow back into the system so you can keep the good oxygenation going while limiting the export.

These are just thoughts. Think it through first and go slow. Only change one thing at a time unless you know exactly what it is.

 

[Lovefish77]

What’s your po4?
What are you doing for nutrient export?

I have a marine pure block that has been in the sump for years, marine pure spheres and a big algae scrubber with a 7x7" screen. I run it now like 7 hours only (used to be 12). I take like a pound of algae every 6 weeks out of this thing. My nutrient export magic is in the sump. I swapped my entire aquascape in the main display 3 months back without any impact to my nitrates. Hope this helps.

 

[EMeyer]

I cant tell from your pic whether the tips are dead skeleton or just pale colored growing tips. The former is a problem, the latter is not.

In my experience when acro tips burn, its either high alkalinity or salinity deviations. Whats your salinity, and have you calibrated your salinity device recently?

On the subject of nutrients vs alkalinity, I dispute that there is any such relationship since the mechanism people often bring up to 'explain' such a relationship is inaccurate. IMO unnatural high alkalinity is just bad for corals, and it has nothing to do with nutrients. Your alk looks fine, so we should look elsewhere.

 

[Lovefish77]

I had this same issue one time. After scratching my head for days we finally figured out it was a trace element overdose. Just something to think about.

If you haven't been dosing trace elements I'd start thinking about your lighting. LED's put out a ton of light. Bumping the lights down slowly could be an option. Of course observing the corals closely. You may have ticked off that big colony.

Take a look at the corals. Are they pale or do they have rich color? If rich color.... I wouldn't do anything to the N&P. If pale....I'd keep trying to raise the NO3. If the PO4 is low I'd try to raise that a little too. If you can't do it by feeding...it may be time to start dosing it back to the system.

In the meantime if you know the numbers are likely low one thing you can do right now is start skimming super dry or pull the skimmer cup off and let it overflow back into the system so you can keep the good oxygenation going while limiting the export.

These are just thoughts. Think it through first and go slow. Only change one thing at a time unless you know exactly what it is.

Thanks. I am not sure whether Acroppwer and Red Sea AB+ have trace elements or not really. Will look at the bottles.
I already skim dry and take like one inch of skim mate every 2 weeks or so. Will test phosphates today and post the result here.

 

[Reefahholic]

Thanks. I am not sure whether Acroppwer and Red Sea AB+ have trace elements or not really. Will look at the bottles.
I already skim dry and take like one inch of skim mate every 2 weeks or so. Will test phosphates today and post the result here.

Roger that. Are you dosing RS AB+ nutrition or is it something else.

 

[Lovefish77]

Roger that. Are you dosing RS AB+ nutrition or is it something else.

Red Sea AB+ the green liquid that looks like alien blood

 

[Reefahholic]

Red Sea AB+ the green liquid that looks like alien blood

That is coral nutrition and as far as I know doesn’t contain trace elements. Do you have a Hanna Phosphorus ULR meter? I’d like to know your PO4 number.

 

[Lovefish77]

That is coral nutrition and as far as I know doesn’t contain trace elements. Do you have a Hanna Phosphorus ULR meter? I’d like to know your PO4 number.

Yes have Hanna ULR. Will test and post here later today.

 

[Lovefish77]

I cant tell from your pic whether the tips are dead skeleton or just pale colored growing tips. The former is a problem, the latter is not.

In my experience when acro tips burn, its either high alkalinity or salinity deviations. Whats your salinity, and have you calibrated your salinity device recently?

On the subject of nutrients vs alkalinity, I dispute that there is any such relationship since the mechanism people often bring up to 'explain' such a relationship is inaccurate. IMO unnatural high alkalinity is just bad for corals, and it has nothing to do with nutrients. Your alk looks fine, so we should look elsewhere.

If you look at the right side of the colony you will see the white growing tips are slightly covered in brownish layer. I blew off some of the film on the left side with a turkey baster yesterday before taking the pics.
On your note of burnt tips, my salinity is stable at 1.025, refractometer calibrated with rodi (0 tds) regularly. Alk is fine like 7.8 to 8 dkh and has been in that range consistently. So not sure what is going on.

 

[EMeyer]

If you look at the right side of the colony you will see the white growing tips are slightly covered in brownish layer. I blew off some of the film on the left side with a turkey baster yesterday before taking the pics.
On your note of burnt tips, my salinity is stable at 1.025, refractometer calibrated with rodi (0 tds) regularly. Alk is fine like 7.8 to 8 dkh and has been in that range consistently. So not sure what is going on.

Thanks! If algae is growing on the tips that sounds like burnt tips rather than growing tips. I do agree that it sounds like your alk is in a safe range.

Refractometers need to be claibrated with a 35 ppt (1.026 sg) solution, not RODI. Some manufacturers have instructions that say to use RODI. This is incorrect. All refractometers should only be calibrated with 35 ppt solution, not RODI. It can make a difference in some cases.

I am not saying thats your cause for sure, but it wouldnt hurt to recalibrate with a proper solution and see if it makes a difference. Randy has a nice recipe here

http://reefkeeping.com/issues/2004-06/rhf/index.htm

 

[Lovefish77]

Thanks! If algae is growing on the tips that sounds like burnt tips rather than growing tips. I do agree that it sounds like your alk is in a safe range.

Refractometers need to be claibrated with a 35 ppt (1.026 sg) solution, not RODI. Some manufacturers have instructions that say to use RODI. This is incorrect. All refractometers should only be calibrated with 35 ppt solution, not RODI. It can make a difference in some cases.

I am not saying thats your cause for sure, but it wouldnt hurt to recalibrate with a proper solution and see if it makes a difference. Randy has a nice recipe here

http://reefkeeping.com/issues/2004-06/rhf/index.htm

Will look into calibration. Seems this is another reef project in itself lol.
Just looked at acropower and AB+ and none of them have trace elements.

 

[Kfactor]

I keep alk at 8 I find if my no3 gets over 5 the tips on my acros start to turn white I think it’s burning them

 

[Lovefish77]

I keep alk at 8 I find if my no3 gets over 5 the tips on my acros start to turn white I think it’s burning them

Sounds right but my nitrates are not above 5. What I read is when you provide more nutrients like above 5ppm no3 corals get in overdrive mode to grow and if the alk does not match (like above 8) you end up with burnt tips as low alk puts a cap on their growth. That is what i read.

 

[Kfactor]

Sounds right but my nitrates are not above 5. What I read is when you provide more nutrients like above 5ppm no3 corals get in overdrive mode to grow and if the alk does not match (like above 8) you end up with burnt tips as low alk puts a cap on their growth. That is what i read.

I would like to know that too I have always wondered about nutrients and alk