This thread was fascinating.
I've been running a 'hands off' tank for about 18 months now.
It runs entirely on dosing (8 channels and a suite of ionic replmeneshment and nutrients)
and doesn't get fed anything other than the occasional flake feeding perhaps once a week.
It's a 75litre tank full of coral, with 3 damselfish and a bicolour angelfish. The tank gets fed N and P and the algae and pods sustain the fish and have done so since the tank was established, however various test periods resulted in lost corals while establishing a strong dosing regime.
I've recently switched out (in the last 5 months) from Aquavitro synthesis to just KNO3 powder and have seen a decline in the 'vibrancy' of some of the corals - after a while, Nitrate accumulated and I wasn't dilligent enoughwith water testing to recognise this. It seems that dosing nitrate has a very narrow window where the corals will start to decline from too little - or too much accumulation.
I've just switched out to ammonium chloride (as I already dose an alkalinity supplement as part of the dosing regime) and so I am extremely eager to see what difference this makes in terms of coral health and any algal population shifts.
I wanted to drop a quick note about the tank,
When i started on this thread, i had another nitrate spike a couple weeks ago so some of the acro frags weren’t the healthiest and my soft corals had slimed over in some instances.
I have been running Ammonium Chloride now for about 5 days, started with a 1/5th strength solution then ramped up to equivalent of 1ppm nitrate per day. previously i was dosing around this level post nitrate spike.
When i started the tank was growing a lot of algae, hair algae, cyanobacteria and some dinoflagellates which i associate with algae’s that can outcompete corals as these have come and gone previously. The tank would need a clean of the glass every 3 days or be impossible to see in (brown and some green algae’s on the glass primarily.
Since switching, i’ve noted that the cyano colonies have disintegrated almost entirely, my LPS and some soft corals that aren’t dormant are showing a kind of “glow” and turgidity that i associate with being well fed (in acropora, the thickness of the coenosarc shows a strong picture into coral health, and this effects how it reflects light, they can look sort of pearlescent)
The algae on the glass have stopped almost entirely and the glass cleaned itself from all the snails, and some of the soft corals have expanded and opened up somewhat.
Based on just this 5 day trial i would say that the ammonium compound directly feeds corals in a way that No3 does not. I now somewhat understand why i had lost the “vibrancy” when switching from a compound nitrogen source to a flat KNO3.
@Randy Holmes-Farley can you advise on whether it would cause any interactions mixing up ammonia chloride with potassium nitrate to create a combined nitrogen source? if not i can dedicate 2 doser channels but it may simplify things.
due to controlling direct dosages of all my nutrients, i get to observe some interesting relationships and ratios over time. based on this short trial I suspect controlling the ratio of ammonium to nitrate dosage would allow for a relative coral to algal growth and i want to combine the two to ensure that some algae grows to sustain the snail and fish/pod population.
will keep monitoring, i’ve upped the ammonium dosage by 50% today, will do a few water tests for records