Which deficiency?

[MacFanMr]

The picture attached is of leaf damage to older/lower leaves on three plants in a well established 150g aquarium. I am certain it is a deficiency of one or more key nutrients. I have begun using PMDD and am sure it will be corrected by that, however for my own information, I am wondering what the deficiencies were?

I have consulted this link Nutrient Deficiency in a Planted Tank and would guess potassium, but several symptoms appear in multiple entries.

I believe it was dosing with only Flourish Excel that resulted in this deficiency as I have not had problems previously. I was under the presumably mistaken impression that Flourish Excel was a comprehensive nutrient source.

Michael

 

[Tom Barr]

Excel is just a carbon supplement.

If you had decent results prior............and you where carbon limited .....then you amplified the growth and switched limiing parameters, perhaps K+, perhaps PO4, etc.

Note, PMDD does not included PO4.
Strong PO4 limitation is not an issue for many low light, non CO2 tanks, however it can reduce growth a good deal in CO2/Excel enriched systems.

Regards,
Tom Barr

 

[MacFanMr]

When I ordered from aquariumfertilizer.com I bought some mono potassium phosphate too, but it was so long ago, I couldn't remember why. I need to review the estimative index system I guess. My phosphates have tested really high all along, a phosphate remover resin brought them down to reasonable levels, but once removed, they returned in time. But after dosing only potassium nitrate in the tank, a week later showed lowered phosphate levels, so in time it may be necessary to add it to the mix. Can I just add it to my PMDD mix? I was using Excel primarily because of its off-label algae fighting properties, the tank has CO2 injection. I was having trouble with brown algae and more recently BGA/cyanobacteria, particularly on top of my driftwood which I read could be a sign of a nitrogen deficiency as near the surface it can get nitrogen from the air. Except for a new leaf on an anubia that looks particularly healthy, I haven't seen any signs of improvement yet, but the BGA I vacuumed out hasn't returned and nothing looks worse off so I'm keeping my fingers crossed.

Michael

 

[Carissa]

I could be wrong but I thought that BGA could fix it's own nitrogen, making it more likely to manifest itself in tanks with low nitrates since the plants cannot fix their own nitrogen and therefore start starving where BGA can grow rampant.

However I've noticed that in tanks where I've had BGA issues, it always grows nearer the surface where possible but also only nearest the light source as well, so I attributed this to the increased intensity of the light. It does not seem to grow near the surface or much at all in lower lit areas of the tank. I also find that it will grow in the flow of water into or out of a filter, I'm not sure why this is but perhaps it's the increased availability of nutrients and/or oxygen in the water flow.

Also it has been my experience that fast growing plants even in non-co2 tanks will show signs of phosphate deficiency in a matter of days if phosphate is completely eliminated (something I tried before I understood what my real problem was). Slower growing plants are not affected as quickly, I guess the same as any type of deficiency.