How to keep most life on KP rocks?

[Miami Reef]

You could do that or you might let it ride and see if it clears on its own. Won’t the coral benefit from this banquet?

Yes, I know they would enjoy. It’s just that I need my UV because I think I introduced ich (it’s mild and under control). I use the water clarity to judge how effective the UV is.

I’m on another forum and people there have tried using hydrogen peroxide to manage velvet. I just don’t think the benefits outway the cons of dosing a lot of peroxide to my tank.

So that’s why I’m using UV for now.

 

[ISpeakForTheSeas]

So, I’ve been researching sponges in particular a bit more recently, and (to add to what I’ve already mentioned in this thread) I figured I’d share what I’ve learned so far as it may help others:

With regards to sponges dying when exposed to air, my understanding is that they essentially get air trapped inside their structure and slowly desiccate and/or starve from not being able to continuously filter the water in and out of their body. I wonder if this condition could be treated successfully using methods similar to how one "burps" a clam or a nautilus (i.e. I'm curious if slowly rotating it 360 degrees underwater multiple times would help relieve the problem/release the air from inside the sponge). I suppose with a sponge you would likely need to rotate it 360 degrees in a number of different directions (i.e. top to bottom, side to side, diagonals, etc.) and/or possibly expose it to some flow while "burping" it to help dislodge any bubbles in the spicules, but - in my mind/in theory at least - it seems like it would help.

I have no idea if burping a sponge that has been exposed to air would help or not, but it may be worth a shot if you’re concerned about a sponge and can attempt to burp it safely.

This next quote may explain somewhat why sponges thrive in one tank but not another:

Yeah, most sponges that I’ve looked into primarily consume dissolved organic carbon (DOC) and specific bacterias, with a preference for algal-derived DOC (i.e. DOC produced by algae). Boring sponges primarily consume DOC (~80% of their total diet, with the remaining ~20% coming from particulate organic carbon (POC - primarily phytoplankton and bacteria). This ratio of approximately 80/20 seems to be pretty typical for sponges from what I can find.

Natural Diet of Coral-Excavating Sponges Consists Mainly of Dissolved Organic Carbon (DOC)

Coral-excavating sponges are the most important bioeroders on Caribbean reefs and increase in abundance throughout the region. This increase is commonly attributed to a concomitant increase in food availability due to eutrophication and pollution. We therefore investigated the uptake of organic...

journals.plos.org

Unfortunately, we don’t have an easy, hobbyist way to measure DOC that I’m aware of, but, there you have it.

Edit: meant to add on, most sponges - as WheatToast mentioned- don’t seem to eat much phytoplankton (they seem to basically just eat DOC and bacteria, though they may consume some small phytoplankton). The phyto may help by being eaten in small quantities, or by producing small quantities of DOC for the sponges to feed on though (so there may be a largely indirect benefit from it).

The info in the quote above applies to heterotrophic sponges, not photoautotrophic (i.e. photosynthetic) ones.

[Edit: The quote below basically implies that the sponges we see on live rock here in the US are likely to be heterotrophic, not photosynthetic (though there are a number of photosynthetic sponges here too, and at least a few that are or can be both, such as Xestospongia muta, the giant barrel sponge):]

“Caribbean sponge species derive much of their required metabolic C through heterotrophic feeding, which contrasts with Indo-Pacific species that rely heavily on photoautotrophy (e.g., Wilkinson 1983, 1987; Powell et al. 2014).”

https://aslopubs.onlinelibrary.wiley.com/doi/full/10.1002/lno.10634