plantbrain
Fishaholic
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That makes perfect sense and explains why unstable, not just low CO2, can induce algae.If you have a heavy bioload like this tank, then suddenly stop adding so much CO2, which drives rapid uptake of NH4 under high light, this causes a back log of NH4, although small, it's often enough to induce some algae species.
Well, they are also linked, poor unstable CO2 will cause a back up of NH4, and so will a large uprooting of plants etc without a fast water change afterwards, or low CO2 reduces the rate of NH4 uptake by the plant(it does not need as much NH4 since it's now CO2 limited, so it down regulates uptake of Nitrogen).
Likewise, adding NH4 will induce algae even if you have good CO2 and nutrients and higher light.
This is why you cannot keep adding fish to higher light tanks to supply all the N neededs without adding NO3's from KNO3 etc, although many do rely solely on fish waste with a wide range of results, adding KNO3 typically improves plant health and vigor a great deal.
In many locations in Euroope and the UK, you have a lot of NO3 in the tap water already.
So 50% weekly water changes with 20-40ppm NO3 adds enough NO3 and then the fish waste along with that adds enough NH4 etc.
So for such tanks, one can use K2SO4 in place of KNO3.
Even if you add more KNO3 and do not use K2SO4 with such tap water, the added NO3 really has never done any ill effects to Discus/Altums and other supposedly sensitive fish species.
Still, as long asd there's ample supplies, and it can come from something like Dirt and sand, ADA aqua soil, or exclusively the water column from KNO3 and/or fish waste, the plants are fine.
It's when you get too far outside of a dosing range that's good for the plants that folks get into trouble.
Too low= stunting plants
Too high= maybe fish issues
I've gone to 120-160ppm a few times for a 3 days peroids to see using KNO3, it did kill off about 40-50% of the Amano shrimp, but no fish where affected.
This Behemoth has about 60 bags of ADA aqua soil, gets standard 3x a week EI and is now packed with weeds that grow rapidly.
The lighting is 4x 1000w MH's, 8x 65w PC's and 8x40W. It's about 850 micro mols/m^2/sec at the surface and about 225 micromols at the lowest point inside the tank.
That's about 8-12 w/gal of PC light equivalent!
At the 4 ft depth, it's aboput like having 3 W/gal over a 200 liter standard sized tank, but the upper part is beyond most all lighting set ups in most tanks.
ADA's large tank is a mere 2400 watts but gets some sun and has a little FL's as well, still, the distance of the MH's much higher/farther than the more efficicent 1000w lights(16" away).
I'd say this tank has about 2x more light.
That makes it much harder to maintain and prune, but we can throttle the light with time duration etc also(typically 8 hour lighting time).
Regards,
Tom Barr