indoor plant ferts for aquarium tank

[phish head]

the info on aquarium plants say don't use ferts that are used for indoor potted plants My question is why? and does anyone use them anyway?

[Expectorating_Aubergine]

Mostly because they are much stronger than what you want to use for an aquarium. Also the nitrogen source is ammonia, so there's that. I personally use dry ferts made for house plants and veggies on my planted tanks. I have yet to have a problem with them. What i have figured is small amounts for dry ferts. I use osmocote pellets too and have the same philosophy as well. I even use dry ferts on my pond. And if anyone reading this was wondering:

-yes I do add the ferts directly into the tank

-yes the fish are in there while I do it

-no, I haven't had fish die from using dry ferts

I think having drift wood in the aquarium helps when doing this. From gardening, I know that dead wood absorbs nitrogen out of the soil and holds on to it. One of many reason why many gardeners will tell you not to add saw dust or wood chips to your soil mix. Whatever you choose to do, do it carefully 👍 

[phish head]

thank you for your reply It was intresting because so many in our hobby are so opposed to anything but the stuff made just for the aquarium which to me seems expensive I think I'm going to experiment in a small tank  and see how it goes .I never have used saw dust in my gardens for the reason you mentioned but I never throught about wood in the tanks in that way

[lefty o]

household plant ferts likely have a good bit of ammonia in them, therefore not a good choice for fish.

[Mmiller2001]

On 12/4/2022 at 6:46 PM, phish head said:

thank you for your reply It was intresting because so many in our hobby are so opposed to anything but the stuff made just for the aquarium which to me seems expensive I think I'm going to experiment in a small tank  and see how it goes .I never have used saw dust in my gardens for the reason you mentioned but I never throught about wood in the tanks in that way

Just buy dry salt. They are dirt cheap.

[Seattle_Aquarist]

On 12/4/2022 at 4:41 PM, phish head said:

the info on aquarium plants say don't use ferts that are used for indoor potted plants My question is why? and does anyone use them anyway?

Hi @phish head

Not only are indoor plant fertilizers much stronger than aquarium fertilizers more importantly the nitrogen source in most terrestrial plant fertilizers is ammonia based nitrogen (i.e. ammoniacal nitrogen).  Ammonia is toxic to most aquatic species including fish, shrimp, and invertebrates.  -Roy