The compost pile is a great place for it. I used to have a aquarium and it will heat up the pile fast

Carey

The addition of all that water isn't going to have a negative effect? I keep hearing "not too wet, not too dry".

The lawn is a good place for it also. Makes the grass nice and green...

If you have plants (houseplants or gardens), by all means, toss that water on them! I use the water from my aquariums every week to water my plants - houseplants every other week, and outdoor plants on the "off" weeks (veggie gardens, roses, perennial beds, planters...everything). The nitrates in aquarium water (that's what you're removing...the ammonia and nitrites are converted to nitrates in the biological filter of the tank) make plants just explode with growth - I doubt any of my aquarium water will ever make it as far as the compost pile. :-)

You can use this water safely even though you add all the chemicals to it?

The chemicals just bind the chlorine/chloramine molocules and heavy metals to make it safe for the fish (because we've added those chemicals to the water first to make it safe for *us*). That's all they do is make the chemicals added at the treatment plant inert...if it wasn't "safe", fish and plants wouldn't be able to live in it...it actually makes it better for plants than untreated tap water, in my opinion.

jamie,

Thanks. I still wouldn't drink the aquarium water though! ;-)

If you're worried about the volume of water, you could put outside in a shallow pan for a day or so. It would evaporate some of the water and leave the nitrates.

Or would the nitrates escape with the water vapor?

Anyhoo, my fish experience tells me that, if you're cleaning your tank correctly, you'll have plenty of fish poo to put on the pile.

LOL - I wouldn't drink the water either - before it hits the aquarium, sure, but definately not after! :-)

No, nitrates don't evaporate...otherwise we wouldn't have to do weekly water changes to get rid of them (they'd evaporate out of the tank).

I was thinking though - I should post a disclaimer. I don't use any chemicals in my tanks aside from the tap water conditioner...I would imagine that if you used anything for algae, ph, medications, salt, etc, then you might want to rethink using that water for plants. I still can't imagine it would be harmful to the compost heap though.

Not that anyone should change their aquarium tending habits, but a well established aquarium with a deep enough (3") sand bed will establish colonies of all the nitrogen cycle bacteria, including the anearobic ones that will turn nitrate back into atmospheric nitrogen gas, which escapes the water.

To do this, you need to keep the fish population below the theoretical max, careful not to over feed, and then be lazy. The current tank has had 40-odd healthy, small fish for the past 12 years, and all we do is top it off with tap water to compensate for evaporation.

Your milage may vary.

Oh my word. I can't tell you how glad I am that I read this thread. If I hadn't, it would be just a question of time before I had a 40 gallon tank sitting in that spot in the hallway. I already have a 10 gallon tank that evolved through a series of poor decisions on my part.

Well, buying bigger and bigger aquariums, and transferring fish, water, rocks, and then re-attaching the hoses and pumps and bubbly pirate chests and adding more water to dilute the nitrates is an option.

So, Annpat, you started off with a small, 1 qt gold fish bowl, and were up to 10 gallons?

Thankfully now drug back from the aquarium SUV precipice.

David--to get the nitrogen cycling correctly, don't you also need plants? It has been many years since I had an aquarium, but I thought that was supposed to be one of the reasons for having plants in the water.

bpgreen, thats another 'tool' for excess nitrate removal - the aquatic plants absorb it, along with other nutrients in the water, grow, and every now and again the aquarium keeper removes a chunk of water weed.

All that works ok, unless you have snails, who are in there to clean the algae off the glass, but find water weeds even better.

Which reminds me of my brother, an aquarium nut with one of those umpty-gallon tanks that require sophisticated engineering to install, who asked his co-worker who was vacationing some sea side place to bring him back some cool rocks for his aquarium. Unfortunately, the rocks carried some aquatic weed seed that promptly, like within 48 hours, filled his aquarium with some kind of green glob that he's never been able to completely irradiate.

If you routinely use sodium thiosulfate drops to dechlorinate the aquarium water, then you should not put it into the compost. Sodium thiosulfate is a powerful fungicide and your compost pile needs all the fungi it can get.

I thought there could be dangers of keeping a deep, anaerobic sand bed in an aquarium though, David...namely that if you disturb those anaerobic pockets, it will release too much gas into the surrounding water, and potentially harm the fish. That's what I seem to remember from reading something, somewhere, long ago (how's that for specific information?). I guess that's where the lazy part comes in...not stirring up the sand bed. I'll pass on that - I like my gravel bottoms.

In any case, I keep houseplant cuttings growing out of my goldfish tank to reduce nitrates - never were there more messy fish than my beloved goldies (a 45 gal. tank...my "almost luxury" sedan of tanks). But there are still plenty of nitrates left for my plants. I'd go bigger if I could, but hubby's here to keep me at a reasonable level of pet ownership. ;-)

We currently have 18 tanks with the largest ones being 60 gallons. We change 80% of the water weekly and a double change once a month.

We raise rare plecos. Many species that people have tons of trouble getting to breed, we have great sucess with.

Most of the large breeders change massive amounts of water as if you do the math, a 10% change will (over time) cause the nitrate levels to continue to rise.

As for the waste water, we siphon into a bucket. In the bucket is a pump with a 75' hose attached. All the waste water goes into the flowerbeds and boy are our flowers happy! We are putting in a new 40 tank system where the water will be able to be routed to the flower beds and the vegtable garden with a pipe and valve system instead of the hose.

I would not use the water if you are treating for disease but in a situation like ours, we dont have disease problems since our fish are all raised by us and any new aquired fish go into a 2 month quarentine.

Short answer, aquarium water is great stuff to water with.

No, Dave, my first tank was 1/2 cup of water containing the least adoptable fish in the world----a brown Beta.

It's been six years now. Fish never die all at once. You're always left with one who needs a friend. The worst mistake I ever made was buying algae tablets for some godforsaken algae eating monstrosity I was forced to buy. I can't even see my fish anymore through the green walls. But I look through the top sometimes and they're all still alive, and look as happy as fish ever do.

if you are having algae probs. then it's probably your lighting regimen. lights need to be limited to less than 7 hrs.
and here's a little trick i found out, even though i keep my lights on a 7 hrs/a day cycle, i still get bg algae and green spot algae on my amazon swds. so do this. leave the lights off for a week or two, or until the algae is gone, the plants will look great.
also weekly water changes never hurt to keep algae @ bay,

jmsimpson9,

I didn't realize such large changes were beneficial - as a first time aquarist (?) I was worried that too much change would inhibit the growth of the good bacteria.

Short story, I've got a spanking new tank with 4 2-3" koi in it. (Read the thread I linked to for why I'd have such a terrible situation going on) and the poor things have gone from very active to slow and lethargic, and the water has gone from sparkling to dull and stinky.

I'm glad to head a bigger change is possible, because I think it would do them some good. Also, it will give me more nitrogen-rich water to experiment with. :)

A 70% change has done wonders for the tank and it's inhabitants. And all of the houseplants, my veggies, and the compost bin thank you all. (The neighbors, with me clunking up and down the stairs to the garden with 5 gallon buckets at 7 am may not be as appreciative :) )

Thanks!

I didn't realize such large changes were beneficial - as a first time aquarist (?) I was worried that too much change would inhibit the growth of the good bacteria.

That thinking is old school and a myth. No sucessful breeder follows it. Some pet stores however continue to tell their customers that and if they had even bothered to read the fish mags they sell they would see, 10 - 20% water changes is no longer recommended.

We change 80%, cleaned the gravel and the filters at the same time and there has never been a rise in ammonia or nitrite levels. We used to worry about it in the beginning but after testing the water parameters after each change, we learned it didnt harm anything.

Koi and goldfish, contary to popular belief, need alot of room. They are big messy fish. Your 40 will not be big enough very soon. You will find yourself either upgrading again to a 60, then a 100 and in time a 200 just to keep the koi in the tank or you will need to trade him back to the place you got him. They get big, to about 2 1/2 feet long and grow up to 4" a year.

Another myth is the fish will not outgrow the tank. What happens there is the water pollution gets so bad that the fish gets stunted, sick and then dies. (think goldfish in a bowl). With proper nutrition and a clean healthy enviroment they will grow and grow fast and live 50 - 100 even 200 years. The record holder koi is 230.

You will need to clean the gravel with every water change, get a siphon with a gravel filter. If you have sand in that tank, get rid of it and switch to a thin layer of gravel or gravel and an under gravel filter plate. Personally we got rid of the under gravel filters and went with a thin layer of gravel as that easier to clean.

You need super filtration even on your 40. Do you have a hang on filter and a cansister filter? You need them.

And as for your original question, is the water good for the compost heap? Your going to generate too much and it will make it too wet. Water the lawn or your plants with it, they will love you for it!

i agree, think about how big a koi gets. there is a rule of thumb that fish need a gallon of water per inch of their body legnth, i think thats wrong, think about putting a ten inch fish in a ten gal. tank, it wouldn't last long.
i have never seen anything wrong w/ sand in aquarium as long as you have filtration w/ aeration.
once my wife unplugged my sand bottom tank, i came in several hrs. later and it was cloudy, and gas bubbles were bubbling up from the sand.....stunk!!! bout killed my fish.

I am in the process of setting up a 45 gallon freshwater tank with plants and fish and would like to know if a continuous flow of water (1 drip at a time) would work as opposed to 20% or 50% or whatever once or twice a week. This way I can set it and leave it without the fuss of dragging buckets or running a 45 foot Python hose through my house to the kitchen sink (the closest faucet). I have a cold freshwater copper pipe in my basement just below the location of the aquarium that I could run the line with a flow restrictor, and the drain could run close by to outside of my house (I can keep it from freezing in the winter).