Rapid reduction of p04, AKA: Speed killing Zoa's.

[Rakie]

So I'm not much of a zoanthid guy. I have a few, and I'm actually picking up a couple more soon, but a few times now I've noticed a mass zoa decline in my tank..

The First Time -- At one point i wanted to really test if nitrate dosing had a positive impact. To my surprise, it absolutely did (for my SPS). I somehow missed the connection between dosing nitrates = Zoa's thinning out and looking sickly. The more temperamental ones shrank away to nothing.. Looking back on it, it all makes sense.

The Second Time -- After awhile I stopped dosing as my nitrates stabilized at a number I liked, slowly, my zoa's came back. Cool! Genuine mystery at that point. So fast forward to getting 3 invasive algae from frag plugs (NEVER trust a frag plug). Water changes, lots of GFO. I didn't notice too much health decline from the zoa's until I started using the large amounts of GFO -- And even then, they were 90% fine! Just a few were a little deflated, no biggie!

Well I remembered that dosing nitrates causes a reduction in phosphates. So lets bring out the ole kn03 again and really take out that p04 issue. Awesome! Well, it wasn't long until my algae stopped growing, my phosphate had dropped to nothing, and all my zoas were looking poor again... Again, total mystery. I assumed it had to do with the algae itself, either robbing the water of nutrients, or physically irritating the Zoa's somehow (algae exploded everywhere almost instantly, it was maddening).

At this point I was thinking the problem could definitely be nutrients. BUT, assumed that it was the algae physically irritating the zoa's due to proximity. Fine. As I regained my ground against the algae and stopped kn03 dosing everything returned to normal.

The Third Time -- Fast forward to a few nights ago. Setting up a new tank, SPS are starting to look good, but the fish are in QT so I decided, "hey, these sticks loved that nitrate. It would probably be a good idea to have a little extra nutrients in the system" Off I go to grab some of that magic juice again.

This time, there were no variables. Tank was algae free. No pests. No irritants. Fish in QT. No annoying shrimp.. And coincidentally, just like the last two times I dosed nitrates, my Zoa's started to.... Bingo.


By this third time I had figured it out. Dosing nitrates dramatically drops phosphates, removing p04 too quickly can absolutely shock zoa's. This is something I've seen mentioned here a few times by others. I hadn't realized just how quickly I was depleting the available p04. This has single handedly, and instantaneously caused many of my zoa's over the past year to suddenly wither. Some of which died, others were just very irritated.

[becon776]

Science!

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[jccaclimber]

Do you think it is the rate of change, the absence, or both? What sort of decrease rate are we talking?

[Rakie]

Do you think it is the rate of change, the absence, or both? What sort of decrease rate are we talking?

Honestly, I'm not sure. It was sort of just a story for those who have suddenly had everything get unhappy -- Maybe a dot to connect, you know?

I would *guess*, it was the rate of change.

I didn't watch my addition of AF Bio S and within 3 days I went from no3 & po4 of 25/.08 to a reading of 0/0.

Before that when my tank was newer, it was absolutely DEPRIVED of nitrates. I had to dose quite a bit to register even trace amounts of n03 in my testing, overnight po4 which was also low but detectable, went from .01 to 0. I had zero nutrients, and nothing was making it better until I dosed kno3, which helped my SPS but absolutely wrecked my Zoa colonies. Most recovered, some did not.

It's hard to say what exact mechanism was triggered causing this. Although three times now, when directly decreasing the po4 levels my zoa's had all showed signs of distress, when the day before they had all been healthy and thriving.

[organism]

Just like vodka dosing can get nitrates to 0 and still have phosphates, KNO3 dosing can get phosphates to 0 and still have nitrates. The advantages of carbon dosing and KNO3 dosing are that you get to feed more which gives corals a better nutrient supply. The disadvantage is you absolutely must feed more. I think the connection between nitrates and zoas that you missed was adding more food :)

[Rakie]

Just like vodka dosing can get nitrates to 0 and still have phosphates, KNO3 dosing can get phosphates to 0 and still have nitrates. The advantages of carbon dosing and KNO3 dosing are that you get to feed more which gives corals a better nutrient supply. The disadvantage is you absolutely must feed more. I think the connection between nitrates and zoas that you missed was adding more food :)

You could definitely be right! I had some heavy poopers in that biocube! Took home an unwanted melanurus, and had an additional flasher wrasse, Geo hawk, Firefish, and Hector's Goby. All of em were overfed, my tank was overskimmed and had a heavy WC schedule, as well as carbon dosing (Vodka & Vinegar).

I thought they were getting enough between everything living in there, but it's very possible they weren't.

[organism]

I was going through something similar and it was crazy annoying, but after I tripled my feeding and switched to mostly frozen instead of pellets everything went ok. I'm still not used to dumping this much food and aminos into the tank, took a few weeks to get to this amount but everything seems to love it :D

[Rakie]

I was going through something similar and it was crazy annoying, but after I tripled my feeding and switched to mostly frozen instead of pellets everything went ok. I'm still not used to dumping this much food and aminos into the tank, took a few weeks to get to this amount but everything seems to love it :D

Oh yeah, if I didn't have a bunch of zoa's id be feeding nitrates regularly, everyone (almost) loves more nutrients in the water.

I've been dosing Brightwell FaStart-M in my new setup, as it's a balanced no3/po4 liquid food. It balances out to an no3 & po4 of 3-5/.01-.03 Additionally, I've only had fish in the DT for a week now, previously it was fishless so heavy feeding wasn't the best option.

I will definitely say that if anyone is having nutrient problems AquaForest Bio S and Pro Bio S are absolutely nuts. They will make your system ULNS in a blink of an eye!

[blasterman789]

I got busy the past few months and after splitting my SPS and Zoa corals to their own tank kind of neglected my zoa tank. Nothing receeded, but growth clearly slowed down in the zoa tank while it accelerated in the SPS tank. My own theories on that later.

I also use potassium nitrate to keep nitrate up in the softie tank, and it had slid back down to less than 5. Most reefers would love this, but with a rapidly growing garden tank with *big* established species of palys growing in baseball sized chunks it's not a good thing. Montipora isn't thrilled about uber low nitrates either.

Still I've not seen much difference in zoa growth or health beyond 5ppm. I've kicked nitrate up to 20-30ppm and it makes no difference. 5-10ppm seems to be the happy point. All my tanks have very low phosphate.

There were however two things I wasn't doing in the softie tank. One was feeding it as much protein. I throw chunks of beef heart in a blender and mash it to a milk like consistency and dump it in my softie tanks as food. Water gets milky, but in heavy garden tanks they filter out the protein and the water is crystal in a few hours. After my gobstopper colonies get back up grapefruit size water will clear in less than half an hour via past experience. Anyways, once I went back to 2-3 feedings a week things improved, but not entirely

The last thing I forgot to do was dose calcium hydroxide / kalk. I discovered a few years ago that generously adding kalk to softie tanks drastically improves their health and speeds up growth. Sick of purple hornets melting on you? Add kalk..... Like adding viagra and fertilizer for zoas / palys. Within 48 hours all my colonies were extending skirts, colored up and started to look much more healthy. The kalk absorbs free acids, but also raises alk. The later isn't good for SPS, which I've moved to another tank, but now on their own all corals are doing better.

Once moved to their own tank my SPS took off again. Reason for that I'm pretty sure is dense amounts of softies dump a lot of C02 into the water at night. Again, I used kalk to correct this, but it throws off alk. My SPS tank is much more stable now and pH runs higher without all the zoas and palys.

[Rakie]

Thanks blasterman, I basically run my tank as an SPS only tank and threw in some zoa's and LPS with the mindset of "If they die, they die". Harsh, but in my experience most Zoa's are bomb proof (Unless I like them, of course).

I run Kalk in my SPS tank and actually noticed nothing but improvement in my SPS, I attributed it to stability in the big 3, and pH. They also like being given kno3, the added Potassium probably aids in color, but the complete loss of phosphates isn't what I'm looking for. I'd really like them to have *some* po4, doesn't have to be a lot, I'm happy as long as they're detectable.