Alk Consuption has stopped ?

[ScottB]

I would get a sample of those diatoms under a microscope. Even money they are dinos given your nutrient deficiency.

If you don't have a scope, look up the coffee filter method to test for dinos.

 

[X-37B]

I feed two cubes of brine and 2 cubes of mysis in the morning between 3 tanks ( roughly 1 cube of each in this tank) and Ocean nutrition Formula 2 flakes in the evening. Occasionally add a sheet of Nori for the tangs once a week. I don’t feed the corals outside of Amino and Pohls Solution from KZ

Honestly,that is not much food.
In my 120 with 14 fish I feed 8 cubes a day.
I do not feed corals.
Po4 ranges .04 to .1
No3 ranges 5-15.
High alk and low nutrients seem to be the issue, imo.
I would feed more to bring up nutrients.
Turn your skimmer back on for export.
I am not a fuge fan.
I would rather run a skimmer and not a fuge.
For me it is easier to control nutrients.
I also prefer an alk of 7 and as close to NSW as you can.
It works for me on two seperate systems

 

[dwest]

I was wondering the same thing as scottb was. If that brown stuff was dinos rather than diatoms, that might explain lack of alkalinity uptake. Having nitrates near zero made me suspicious.

 

[ScottB]

Agree with @90's reefer that your nutrient input is far too low to run that level of residual nutrient. If you told me you had those levels, but were feeding 4-8 times a day I would say that is really cool and carry on.

 

[Nano sapiens]

My interpretation is different: they starved the corals, and just like with burnt tips at high alk, the tissue could not keep up with skeletal growth and that messed everything up. It's not a high alk effect per se, it is high alk with insufficient N and P:

"Nitrate and nitrite generally peak when excess nutrients are added to a system which could cause stress among corals. It was important to maintain these at 0.00 mg/L during the entire duration of this experiment (Hughes et al. 2003). "

I see where you are going with this. I scrolled through this article looking for the test duration and here's what I found:

The fragged corals were then uniformly distributed and acclimated into seven different experimental tanks (three frags of each species per tank). All tanks were cultured 2 months prior to the time of acclimation.


...and fluorometry sampling was taken after one week:

Water Quality Manipulation​

A 33% solution of Hydrochloric acid (HClaq) was used to reduce and maintain a low pH of 7.9 in the “Low pH” system. This was achieved by dosing 0.25 mL of HClaq every 10 minutes for ~2-3 hours, 3 times a week for one week prior to the fluorometry sampling dates. The “High pH” system was dosed with a 42 % solution of Limewater and maintained a high pH of 8.35-8.40. The dosing procedures were the same as those of the low pH.

IMO, not very clear regarding the testing duration, but you are more familiar with these scientific tests and maybe you can see something I don't. But if the sampling was done after just one week of the frags been added to the systems, they should have had enough energy reserves to cope with a low nitrogen situation...unless they were not fat and healthy to start with. As usual, many variables that can effect an outcome.

 

[Matt1508]

Thanks all, however the Dino (your likely right but I’ll perform the test to check tomorrow) only occurred after raising the nutrients, they weren’t ever present at ULN levels.

 

[Nano sapiens]

There’s no doubt that elevated Alk did not suit my tank, with low nutrients and fairly high par it was never going to go well.

just unsure now where to keep the nutrient levels, tank was happy at near zero but ultimately dropping to unreadable is the only change I can tell of that may have caused the issue, now I worry I’m feeding diatoms unnecessarily?? Will they burn out if I continue to rise or will I just create another issue lol I love this hobby ... but sometimes ..

Yes, fun little hobby we have here

I can't speak for others, but for my two experiences with this I simply went for the 'keep everything at typical reef parameters and stable' for a few months and slowly things got back to normal. I also had the sand bed 'diatom' condition (old tank that naturally runs undetectable PO4 and nearly undectable NO3) for 9 months or so. With a regular maintenance schedule including sand bed vacuuming it eventually disappeared.

 

[Matt1508]

It’s quite possibly exactly this, the Alk issues I had were pretty significant, and likely a mixture of this destabilising event, then bringing the Alk back to normal levels of 8 another stressing event, and then raising the nutrients, even though it was very minimal 0-0.5 ppm over a week was possibly enough for them to take hold ?? they appeared within 36hrs of dosing Nitrates, incorrectly assumed the refugium would out compete the Dino/ diatom - Any other advice would still be greatly appreciated though.

I’ll pickup a microscope to correctly ID Dino or Diatom and just try to leave alone as much as poss.

 

[Nano sapiens]

It’s quite possibly exactly this, the Alk issues I had were pretty significant, and likely a mixture of this destabilising event, then bringing the Alk back to normal levels of 8 another stressing event, and then raising the nutrients, even though it was very minimal 0-0.5 ppm over a week was possibly enough for them to take hold ?? they appeared within 36hrs of dosing Nitrates, incorrectly assumed the refugium would out compete the Dino/ diatom - Any other advice would still be greatly appreciated though.

I’ll pickup a microscope to correctly ID Dino or Diatom and just try to leave alone as much as poss.

Regularly vacuuming the top sand layer to remove the nasties does work over an extended period of time. The key is regularly and persistently keeping at it.

Good luck!

 

[Randy Holmes-Farley]

I see where you are going with this. I scrolled through this article looking for the test duration and here's what I found:

The fragged corals were then uniformly distributed and acclimated into seven different experimental tanks (three frags of each species per tank). All tanks were cultured 2 months prior to the time of acclimation.


...and fluorometry sampling was taken after one week:

Water Quality Manipulation​

A 33% solution of Hydrochloric acid (HClaq) was used to reduce and maintain a low pH of 7.9 in the “Low pH” system. This was achieved by dosing 0.25 mL of HClaq every 10 minutes for ~2-3 hours, 3 times a week for one week prior to the fluorometry sampling dates. The “High pH” system was dosed with a 42 % solution of Limewater and maintained a high pH of 8.35-8.40. The dosing procedures were the same as those of the low pH.

IMO, not very clear regarding the testing duration, but you are more familiar with these scientific tests and maybe you can see something I don't. But if the sampling was done after just one week of the frags been added to the systems, they should have had enough energy reserves to cope with a low nitrogen situation...unless they were not fat and healthy to start with. As usual, many variables that can effect an outcome.

FWIW, I have no idea how long it takes corals in a high alk environment with 0.00 ppm nitrate to suffer.