...delicious for your houseplants, that is.
Fish tank water is one of the most nutritious things you can give your houseplants. Aquarium water is high in nitrogen and phosphorus and potassium, the same components in many plant fertilizers.
You could use siphon to suck the water out into a watering can (and you should, occasionally, because you need to clean the other junk from the tank), but a spigot on the side of the tank will let you cleanly take smaller amounts of water in between tank cleanings. Just pour the same amount of conditioned water back into the tank from the top to replace what you take from the spigot.
Delicious, nutritious aquarium water. Straight from the tap.-- swimswim, Sep 05 2022 Could you adapt this? https://www.amazon.com/dp/B07Y7XPPVR/Rain Barrel Faucet Kit 3/4 Inch Rain Barrel Valve with Bulkhead Fitting Adapter for Water Tanks, Aquariums, Tubs, Pools [a1, Sep 05 2022] Drink Dispenser to Fish Tank https://www.pintere...288441551104724409/Same idea, but this is a repurposed drink dispenser rather than a purpose-built fish tank that has a built-in spigot. [swimswim, Sep 05 2022] Found a faucet kit intended for rain barrels (link) and the marketing blurb suggests it could be used for aquariums.-- a1, Sep 05 2022 Do this with an automatic timer and tubes to plants surrounding the fishtank (which would be pretty) and you've really got something here. [+]-- doctorremulac3, Sep 05 2022 @a1 - that's the general idea, yes! I also just now found a drink dispenser repurposed as a fish tank. I'm not sure if that counts as prior art, but it's pretty close. Link added.-- swimswim, Sep 05 2022 That looks like prior art to me, but it’s a pretty small aquarium. I thought you were after something bigger. Does yours have any gear like pumps, filters, etc., that run tubing outside of the tank itself? Might be better to tap into those than adding a new hole in the tank.-- a1, Sep 05 2022 My own tank is a standard 29 gallon (ahem, 109.777 liter) tank with no spigot or tubing other than an air hose. But the idea is, like you said, to have a spigot on a much larger, common size aquarium.-- swimswim, Sep 05 2022 I'm not sure what the difference is between a tank with a drain plug, to which aftermarket spigots like the one linked can be easily fitted to, vs a tank with a dedicated spigot. That seems to be the perfect solution to what you're looking for, but I'll stay neutral on this one.-- 21 Quest, Sep 05 2022 +I love this, but making sure there is a screen so little fishies don’t come out.-- xandram, Sep 05 2022 Good point, xandram -- probably just like the grates that are used around pump water intakes.-- swimswim, Sep 05 2022 Eau de poisson.-- whatrock, Sep 05 2022 Thanks, now I've got Rene Auberjonois' rendition of "Les Poisson" stuck in my head.-- 21 Quest, Sep 06 2022 You can do this directly, drilling a hole low down in a tank is possible but it comes with dangers. You can't drill tempered glass that you find on the bottom of most tanks and the walls of larger tanks. On glass you can drill, you could easily add a tap, but this leaves you open to leaks and cracks propagating from the hole.
This is much easier to do with external filtration. Typically, a tank is drilled & fitted with an overflow which drains to a sump where various complexities of filtration happen and you can easily fit a tap somewhere in the pipework.
I have a canister filter on a couple of my tanks, I've added a Y-adapter and dual valves so that I can easily drain a couple of gallons using the canister filter pump to do the work.-- bs0u0155, Sep 06 2022 Wash down your Gourmet meal with a Gourami drink.-- AusCan531, Sep 07 2022 Doesn't this already exist? {as shown in link) ie totally baked.-- xenzag, Sep 07 2022 Use a simple duckbill valve to control flowrate.-- RayfordSteele, Sep 09 2022 random, halfbakery