Water test results from Aqua Medic - Whats causing Cyno

[jh2pizza]

I have had issues with Red Turf Algae growing all over the rock for 5 yrs or so. Its not Cyno, but recently I have had issues with Cyno. Does anyone see anything that far out of line that could cause issues with Cyno?


Ammonia (NH3-4) Good 0 0.000 - 0.050 mg/L
Nitrite (NO2) Good 0.004 0.000 - 0.100 mg/L
Phosphate (PO4) Good 0 0.000 - 0.250 mg/L
Nitrate (NO3) Good 0.8 0.000 - 25.000 mg/L
Silica (Sio2-3) High 1 0.000 - 0.500 mg/L
Potassium (K) Low 183 350.000 - 450.000 mg/L
Ionic Calcium (Ca) Good 140 100.000 - 300.000 mg/L
Molybdenum (Mo) High 0.4 0.000 - 0.300 mg/L
Strontium (Sr) Good 7.7 5.000 - 12.000 mg/L
Magnesium (Mg) Good 1400 1100.000 - 1400.000 mg/L
Iodine (I) Low 0.02 0.030 - 0.090 mg/L
Copper (Cu) Good 0.03 0.000 - 0.100 mg/L
Alkalinity (meq/L) Good 3.6 2.500 - 5.000 meq/L
Total Calcium (Ca) Good 420 350.000 - 450.000 mg/L

Should I dose Potassium? If so, any suggestions as to what I should use?

I plan on replacing the Silica prefilter on the RODI.

Also, have a question about Molybdenum. Its not high in the new water but is in the tank water. What could be driving that number up?

 

[biom]

Quite often Cyano bloom is not directly connected with water chemistry but with biological, bacterial imbalance, light, flow etc. Did you double check Potassium with other tests? 183 ppm is very, very low. More information on salt brand, water changes will be helpful.

 

[jh2pizza]

I do a 50 Gal a week water change on around a 280G system using reef Crystals. I had my new water tested as well and it come back low on Potassium as well.


Sammie and I have salt from the same batch and his come back low as well on both test.

We each had new water tested as a basis and our water tested from the tank.

 

[RussIV]

cyano only needs carbon and light. (and a little n and po4 for photosynthesis)

your nutrients are terribly low and it will cascade for cyano to take over even more due to lack of competition.

get nitrate to 2ppm. start dosing mb7 and stability to compete with cyano at night. keep nitrate above po4 in a 16:1 ratio.

potassium has nothing to do with cyano. i had 418 ppm potassium and received a cyano outbreak due to neglect.

 

[jh2pizza]

Potassium - What do you use to dose it? I bought two little fishies and it will take several bottles. Mostly water.

 

[bertoni]

You might be able to find some potassium chloride somewhere that would be fine for dosing potassium, although I don't trust Aqua Medic's testing enough to do that, personally. Their numbers have been odd in the past. I would ignore the molybdenum result, as well. It might be false, or due to some old batch of salt or supplement, but I doubt it's dangerous.

I don't see anything that might cause a cyanobacteria bloom in particular. I'm not sure what the red turf algae is, but algae can be persistent. I might try a bit of GFO and see whether that can reduce the problem over time.