Are alginate and plaster of paris reef safe?

[karimwassef]

just thinking of using some new materials... anyone know?

[jayball]

just thinking of using some new materials... anyone know?

Plaster does not hold up long term under water, will melt in short order. I do not know anything about the other but it looks like it breaks up easy?

[theatrus]

It's CaSO4·2H2O when hydrated, so should be fine (though using too much will move the sulfate/chloride balance). Immersed in water it will dissolve - I believe it's the material used for self feeding blocks.

I've also seen alginate used this way. May cause skimmer mayhem.

[bertoni]

I'd expect both to degrade fairly quickly.

[karimwassef]

So they could both be used to make slow release food without concern.

[bertoni]

The plaster of Paris might be fine for that. I'm not sure about the alginate. It might decay too rapidly.

[theatrus]

The plaster of Paris might be fine for that. I'm not sure about the alginate. It might decay too rapidly.



I had a trial block of an alginate slow release food that was bundled with some boxes of Reef Crystals. It decayed pretty fast (2 days or so) - might be a good tang food source but not very long term.

[karimwassef]

Isn't alginate edible by fish anyway? Bring a seaweed biproduct?

[karimwassef]

I'm wondering if either can be used to slowly release powder coral food like reef roids.

So make a mix of the stuff and put it in the tank close to a power head. Every time the power head pulses, it releases a little coral food from the plaster matrix.

To keep it from melting too fast, I could keep it in a plastic box so only one surface is exposed to water directly and that's what would see the powerhead flow.

The idea is to make something large enough to support the tank for a month without manual feeding and control the dispersal by turning the powerhead frequency and time.

[bertoni]

Alginate probably is edible, but I'd stick with something less processed. It might be a bit unbalanced as far as nutritional content.

Your plan might work, but I'd worry about the food decaying as it becomes hydrated. There are feeders that keep the food dry that should work for this application, although I'm not sure how adjustable they are.

[karimwassef]

This is powdered food like reef chili and frozen food like cyclopese ... I would think that capturing it in a matrix that slowly dissolves would work.

Maybe I need to consider a shellac covering too so that only a small percent of the surface area is hydrated at a time.

[jayball]

This is powdered food like reef chili and frozen food like cyclopese ... I would think that capturing it in a matrix that slowly dissolves would work.

Maybe I need to consider a shellac covering too so that only a small percent of the surface area is hydrated at a time.

Instead of that way, I think the same end could be reached by using a short piece of PVC with one end capped. You are handy enough to rig up a way to keep the opening in front, offset, from the end of the powerhead. This way you do not have to worry about what shelliac degrades to in the reef and you can limit surface area with a small diameter tube allowing a higher concentration of food to the PoP.

[karimwassef]

So fill a pipe with the plaster and position it to catch the flow.

[jayball]

So fill a pipe with the plaster and position it to catch the flow.

That is the best idea I can come up with without playing with it. If the RR and the cyclops are both dried an auto feeder and feeding ring may still be a better idea though. Anything that can feed flake and pellet shouldn’t have an issue with small particle food, you’ll just have to adjust the feed gate smaller.

[karimwassef]

High resolution feeders are not cheap.

I'm a big fan of continuous feeding ... small quantity all the time vs one/two times a day.

I did try to modify a feeder and without a high accuracy stepper motor, I can't get there.

I am thinking of other options including using a algae based gel matrix and a dosing pump.

If making a plaster block in a PVC tube works, that would be a reasonable option.

I'm thinking of putting these blocks into frag holders so the food is always available and in the immediate vicinity of the coral polyps.