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Freshwater Fish tank water as nutrient supplement?

Discussion in 'Nutrients' started by minnesmoker, Dec 27, 2012.


    minnesmoker ɹoʇɐɹəpoɯ

    I'm quite certain that if I were to keep adjusting my search I'd find the answer, but, I couldn't with the initial search. So, the question is simple -- I can set up a freshwater aquarium, plant aquatic flora in it and have a stable biosphere in 2 weeks. A 65 gal. would easily host 2-5 medium angelfish, a cleaner fish and a couple dozen of either guppies or mollies. (1 male to every 10 females, roughly.) With the water, you get plant die-off, fish excrement, urea, baby fish (that's what the guppies or mollies are for.) All those nutes, in a stabilized and fairly consistent medium, fully under your control and supervision.

    Anecdotal Comparison:

    In the past, I ran a couple hundred gallon setup, and the water worked miracles for herbs, flowering, and fruiting plants (roses, tomatoes, etc.) A properly maintained tank will have all of the benefits of a freshwater (river/lake) supply, but none of the external contaminants (bacteria from other plants/pollution/pesticide runoff, etc.) The 65 gallon would produce 6.5 gallons of enriched water weekly (or 13 gallons every 2 weeks, a regular "water change cycle". (20% water change))

    The Question:
    Does anyone have experience with using freshwater TANK water for nutes or nute supplements? If so, please share your experiences, as I'm really debating setting up a tank or 2 but, only if it'll be beneficial! I've already replaced my growing fish hobby.

    cheechako Well-Known Member

    Large scale grows (vegetables) are done using the water directly as a form of hydroponics known as aquaponics. It would be hard to do on a small scale because the level of nutrients needed by the plants is probably too much pollution to the fish.

    However, I thought it was common knowledge for anyone with houseplants and fish tanks to use the water-change water to water the plants. When I had planted aquariums, I never had anything growing above water, so I never tried this myself. Google "aquarium water for plants".
    minnesmoker likes this.

    minnesmoker ɹoʇɐɹəpoɯ

    Thank you for the reply. As I said, I've done it in the past, with amazing results -- just never with cannabis specifically. I guess it was a stupid question; a lot of the herbs are more sensitive to nutrients in the soil than cannabis. Thanks for the name! Aquaponics. I'm looking into that now.

    I know that piranha and goldfish are the messiest eaters, and would work best. I'd rather avoid the piranha, just because it's really messy and using that water would lead to seriously foul odors. Goldfish are ugly to me. Mollies/guppies are live bearers and are pretty messy. And, Angelfish are sensitive to environmental pollution. That's why I suggested those fish in an aquarium. So, looks like the next step in my grow-room setup will be a nice fish tank.

    barbz Member

    I used to put used guppy water from my 20 gallon tank on all my indoor plants. None were THAT plant, but things did seem to flourish. However, for a grow I stick to organic nutes. I know what I'm getting there.

    minnesmoker ɹoʇɐɹəpoɯ

    I have absolutely NO idea why I actually posted this as a question in hindsight. I have done it with consumables, just fed the tank with organic fish food, and filtered the water prior to watering. Maybe it's because I hadn't read up on aquaponics yet.

    I'm looking to set up a fish tank, now. I'm starting with a small one, 20 gallon, and going to bio-overload, add a 10 gallon "live filter tank" and a biowheel filter system. Similar to a marine aquarium with coral/anemone. That setup will provide good nutes for a 12/12 continuous grow.

    I understand on the desire for organic -- I think that using actual biologically produced nutes, in their raw form (paper filtered freshwater tank water, from a tank that is a properly set up ecosystem and organically maintained.)

    racerboy71 bud bootlegger

    lol, you don't get much more organic then fish shit imo.. :D

    minnesmoker ɹoʇɐɹəpoɯ

    Disco! From ass to soil... Only way to get fresher is to go full aquaponics!

    intenseneal Well-Known Member

    Yeah I feed my vegging plants fish tank water every few watering and my flower/pepper garden out side gets fish tank water as well. I have green lush plants and my habanero plant exploded and produced over 50 large peppers, super hot too.

    jondamon Well-Known Member

    In a properly "cycled" aquarium the end result is NITRATE.

    This nitrate can be readily used by plants.

    However what would concern me using this water with such a high value crop is possible infections in your aquarium causing problems in your plants. For instance fin rot, internal parasites, fish TB, not to mention the algae that can grow in aquariums could be transferred.

    I own a 50g community aquarium that's moderately planted. In order to sustain the aquatic plants I have to dose water soluble ferts.
    Also thanks to the fish shop that I got my plants from I now have a thriving population of springtails living on my water line of my aquarium.

    Personally I see the uses that it can have but unless you're going full aquaponics why risk contamination?


    intenseneal Well-Known Member

    ^^^ Nitrate and phosphate from the fish waste and foods that we feed to the fish, which are both important nutes to plants. My tank is lightly planted and still has more than enough to feed the plants and have extra nutes left to boost my gardens. Aquatic algae can not live in soil neither can fish diseases or parasites plus the fact that most of us let the soil dry out before watering again so that alone would kill the algae ect that maybe in the aquarium water. I dont know about other peoples aquariums but mine is very healthy and clean and stays that way pretty much on its own. I have 8 tetras that are 3 years old and big now, a breading population of guppies and mollies and a couple of corry cats to clean up the bottom. That little 38 gallon tank is so hands off and simple compared to my saltwater reef aquarium.
    Digger Dave

    Digger Dave Member

    When i had a tank, i used to use that nasty fish shit on the bottom of the tank.Stink!!! well yes, but it do work!...Well i might add.

    minnesmoker ɹoʇɐɹəpoɯ

    That's the stuff I was going to paper-filter (a coffee filter) out, before using the water. During flowering (especially) I am not keen on stinking up the room any more. You have experience with using the whole "load" and it works great, though? If so, I'll just have to add more scent abatement to the room.

    Setting up my tanks and will start cycling it later today or tomorrow. A few skirted tetras (not as sensitive as Angel fish, and need a PH in the same range as the live bearers and the plants) a few plants (quarantine in a separate tank for a few days, to make sure there's nothing hitch-hiking) and a half dozen female guppies, plus a male.

    WOLFMANIZ Member

    Hi Minnesmoker, I use my 55 gal. fish tank to grow my plants. I float a Styrofoam that I cut holes in to fit plastic netted pots. I germinate my seeds in rock wool and then float them in my fish tank. I do diluted Miracle grow in a spray bottle and spray my plants. The guppies don't seem to mind it. As the plants grow the water level gets lower so I don't have to play with the lights. I covered the glass with construction paper to keep the light off the roots.
    Work just fine.
    Happy growing..

    aquastoner Member

    Hey you want to look up AQUAPONICS that is what your doing you may need to change a few things but you will have all needed materials sounds like. I have a large 1100 gallon aquaponics system growing veggies and let me tell you they grow like its no ones business,just have to keep up with bugs should be ok if in green house, use lady bugs they work.Ill get some of my pics out from my farm, i did manage to squeeze a baby in one once and 22 inches in 2.5 weeks from a 5 in cutting, to me thats alot of growth.But like everyone says Ph will be your battle filtration is the answer how ever much water you have you need twice the grow space for filtration.Any questions just ask .I wont hold your comments in my other post against you lol

    aquastoner Member

    And best type of fish would be carp like a goldfish or a tilapia (check your area for laws keeping these)

    Vindicated Well-Known Member

    I guess I must be the only one that tried it and didn't come away impressed. Its a smart way to use water that would otherwise be thrown down the drain, but that's it. I wouldn't encourage anyone to go out and buy an aquarium just to do this. However if you already own one and enjoy raising fish, then it makes sense to try it.
    Stinky Buds

    Stinky Buds Member

    I've got a 220g South American tank w/an Oscar, a Chocolate cichlid, a Severum, an Eartheater, 6 silver dollars and a little pleco.
    I change half the water every week, changing out my 8 gallon res with it.
    Because I change the water so often, the nutrients in the tank are quite low (5-10 ppm nitrate), it doesn't hurt.
    Tankwater that otherwise goes down the drain (except in summer, the wife uses it in the garden).
    Tankwater is dechlorinated.
    Tankwater has low levels of nitrate which plant eat.

    zack66 Well-Known Member

    I used to have a bunch of freshwater tanks and fed the water to my outdoor plants for years. It worked great. As long as the tank is well maintained you should be good to go.

    Kyanite393 Member

    I used it to germinate my seeds, and I water all my house plants, and my clones/seedlings with it as well... why not take advantage it's like a free fish emulsion fert.

    /edit Oh yeah and I don't filter out all the gnar gnar from in the gravel I dump it in with it.
    Stinky Buds

    Stinky Buds Member

    I'm not growing in soil, or I'd be using the "gnar gnar" and the stuff I pull out of my filters for the girls...
    The wife loves that stuff for her garden too.


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