Osmocote dosing?

[KTpoopenstein]

I just discovered that I could use osmocote (which I already have) for NPK in my tank. What would the appropriate dosage be for a 15 gal tank? Aside from buying gel caps to put it in, what's the best way to apply it?

 

[bud29]

You can freeze a few prills in ice cubes and dose in the substrate that way, if you don't want to buy gelatin capsules. You will want to just keep it as a substrate fertilizer, though, because it contains ammoniacal nitrogen - it will cause ammonia spikes if you try to use it as a water column fertilizer.

 

[KTpoopenstein]

You can freeze a few prills in ice cubes and dose in the substrate that way, if you don't want to buy gelatin capsules. You will want to just keep it as a substrate fertilizer, though, because it contains ammoniacal nitrogen - it will cause ammonia spikes if you try to use it as a water column fertilizer.

Any suggestions for how much to use? My tank is 13"x"13" with about 2.5" of gravel (I know sand or plant substrate would be better)

 

[KTpoopenstein]

Oh, and I have the following plants:

Amazon swords (2 smallish bunches)
Java fern (1 smallish bunch)
Water wisteria (3 stems)
Cardinal plant (3 small bunches I just planted a few days ago)
Moneywort (interconnected bunch with half a dozen stems, also recently planted)

 

[bud29]

I know that one 00 sized gelatin capsule filled with O+ will fertilize about a 6"x6" area max. I'm not sure how many prills there are per capsule, maybe 15 or so? I know some people have just put a thin layer of O+ on the bottom of the tank and then put the substrate on top of it, you could maybe do that if taking out your substrate temporarily wouldn't be too much of a hassle. Don't overdo it though, or you may get ammonia spikes.

 

[KTpoopenstein]

I know that one 00 sized gelatin capsule filled with O+ will fertilize about a 6"x6" area max. I'm not sure how many prills there are per capsule, maybe 15 or so? I know some people have just put a thin layer of O+ on the bottom of the tank and then put the substrate on top of it, you could maybe do that if taking out your substrate temporarily wouldn't be too much of a hassle. Don't overdo it though, or you may get ammonia spikes.

Taking the substrate out would definitely be a big pain in the butt, but I'm going to have to do some aquascaping before long to rearrange things to accommodate a piece of driftwood I have soaking so I could probably work it into the substrate when I do that. I'm in the middle of cycling the tank again (long story) so I've been testing several times a day and doing lots of water changes so if anything spikes I should be able to catch it pretty quickly.

 

[jetajockey]

I just did a tank with an osmocote layer.

In your case you'd be fine just putting some down at the base of your heavy root feeders like the swords. You will want to be conservative with it for the reason bud mentioned.

 

[KTpoopenstein]

I just did a tank with an osmocote layer.

In your case you'd be fine just putting some down at the base of your heavy root feeders like the swords. You will want to be conservative with it for the reason bud mentioned.

Would I be ok just shoving some down into the substrate around the swords or would you still suggest going with the ice cube method or similar? It looks like the ice cube trays we had went away during our recent kitchen reno so I'd have to go buy some to do the ice cubes.

 

[jetajockey]

You could use tweezers, the ice cube thing just makes it a lot easier.

 

[KTpoopenstein]

You could use tweezers, the ice cube thing just makes it a lot easier.

That's kinda what I figured. I found some tiny cheap Tupperware things while I was out today so I've got a couple in the freezer now. Hopefully the driftwood will be ready to go in soon and I can rearrange everything in and put in the osmocote in one go.

 

[KTpoopenstein]

So my swords were starting to look a little sad so I went ahead and tried to plant the osmocote ice cubes...the operative word here being "tried". The stupid things popped right out of the gravel and floated to the surface and within seconds had melted enough to release every single bit of the osmocote which scattered all over the tank. Sooo, any suggestions for how to get the ****ed things to stay where I put them?!

 

[jetajockey]

So my swords were starting to look a little sad so I went ahead and tried to plant the osmocote ice cubes...the operative word here being "tried". The stupid things popped right out of the gravel and floated to the surface and within seconds had melted enough to release every single bit of the osmocote which scattered all over the tank. Sooo, any suggestions for how to get the ****ed things to stay where I put them?!

Ahh yeah, it can be annoying, it takes speed. The gel caps make it a lot easier since they don't dissolve immediately. If yo have some natural clay you could roll it in that and it would help have a means to get it down into the substrate.

Another option would be to take nearly all of the water out of the tank, do the ice cube method again (would be easier since there's less water to contend with) and then refill.

 

[KTpoopenstein]

Ahh yeah, it can be annoying, it takes speed. The gel caps make it a lot easier since they don't dissolve immediately. If yo have some natural clay you could roll it in that and it would help have a means to get it down into the substrate.

Another option would be to take nearly all of the water out of the tank, do the ice cube method again (would be easier since there's less water to contend with) and then refill.

I'll give that a try when I rescape to put in the driftwood I have.