How often do you do a water change?

[Interfecus]

I'm curious as to how often people do water changes on their aquaria and how much is changed in each go. I personally change 25% weekly on all my tanks (1 x 20L ; 2 x 40L ; 1 x 60L) but from what I've read here it sounds like this is a bit more than is required. I don't intend to reduce water changes if it turns out that I don't need to but I'd like to know for future reference. Please could people answer this poll and post with rough tank sizes, filtration used, frequency of changes and amount changed. If you change with a frequency not listed in the poll, please round to the closest. Many thanks in advance .

Interfecus

[Interfecus]

If you have several tanks, please just pick one to answer for. A list of everybody's total tanks would take too much space .

[Ira]

50% weekly...Ok, been a bit slack this week...But anyone that says you should be doing changes like 15% every couple weeks is either an idiot or you've got a big, heavily planted tank with very little bioload.

[ajbroome]

Interfecus,

I *try* and do a 25% change on all my tanks weekly. I used to be very good at this but have slackened off lately so it's more like 25% per fortnight (half the tanks each week). I *need* to get back to the weekly thing.

Andrew.

[Caryl]

I rarely do water changes. They would get 4 or 5 a year if lucky. Lots of plants, light stocking.

[Rob]

I change 25-33% of the water a fortnight - don't dedicate a day to it though, just work through the line up of tanks doing one or two each night.

[catfish_dude]

20% for all my tanks weekly.

70g cannister

40g cannister

10g power filter

[herefishiefishie]

Most tanks here are on a weekly water change, about 20-25% though the discus & ghost knife tanks are on a 4 to 5 times a week, little changes.

Frenchy

[Kriber]

3ft x 1.5 1.5 - Community tank, about 40L per week (~25%).

2ft x 1 x 1 - Swordtail fry tank, 16L per day (~33%).

Oh how it is fun!

[Pegasus]

I mainly do a 30% changes very fortnight, but sometimes just top up to compensate for evaporation. If the tanks were all planted I would be perhaps only doing monthy ones... if that ... but the majority of my tanks are bare bottom and the muck looks unsightly, so every fortnight is about the average. Every tank has a filter of some description, mainly box types.

I've been doing a trial with one of my two footers.

It has a simple home-made undergravel filter... nothing else, and it hasn't had a water change for over a year.

The fish (30 odd guppies and a few Cory's) are as healthy as can be and breed quite often, and the water is crystal clear. I haven't lost a single fish from this tank since it was set up and have obtained some good looking fish from the drops they have given me.

It does however have a fair bit of plant growth in there.

This wouldn't work for all situations, but I do feel that some people go overboard with this water changing business.

Having said that, I have on occasions replaced 40% of the water once a week on some of my various fry tanks and such.

You can never get an acurate answer to this question (that is often asked) for each tank is different... fish stocking levels... amount of plants... filtration... size... temp... pH... even lighting... amount of feed given... how often fed... types of food..fatty/non-fatty... water supply... ect.. etc... etc... the computations are enormous.

[Doc Holiday]

I do a 25% water change every Sunday morning, but only due to the huge amounts of waste created by the oscars. My 20L betta tank only gets a 50% change once a month and I'm sure that this only precautionary rather than nessecary.

Like pegasus said, everybodies tanks are different and I'm sure most people do unnessecary water changes.

The general rule is to use your nitrate test kit to monitor your tank, and when your nitrate readings start going beyond 100 then it's time to do a water change. People will find that heavily planted tanks with low stocking levels will take a long time to reach this level if at all. And heavily stocked and unplanted tanks will reach this level very rapidly. My tank takes about 2 & 1/2 to 3 weeks to reach this level and i have huge amounts of waste. But I do my water changes once a week to clean up the extra large oscar poos all over the gravel (messy pups) rather than to keep the water at a healthy level.

I would suggest testing and monitoring your tanks over a 2 or 3 month period to see what each tank requires and then decide how often you feel comfortable doing water changes on each of them. This could be a major time saver due to unessecary water changes.

Good luck

[Joze]

Ido a 50% change on my oscar tank once a fortnight, its bare as in glass only no plants no gravel the only biological input is the filter which I clean alternate weeks. I do one thing which tends to amuse people though, I use a pool vaccum bush hose and pool pump to empty. Which means I can give it a good scrub and pick up everything without disturbing the fish. They dont mind the brush in the tank but get a little iffy if only the hose is in there. I need something to preheat/treat water though and it looks like the only think may be a header tank in the roof for this.

[Pegasus]

Great posts guys... love the bit about the pool pump

I suppose you could store a few gallons in the hot water cupboard if you have space Jaze.

[Joze]

will get a pic of my cylinder for you at some point, ....its in the basement sitting on a concrete pad, I keep tanks in there with it.

[Fish_Tank]

I do a 20% water change every week but don't gravel vac as i have quite a few plants. as I just got a new tank and it is cycleing at the moment i'm not doing water changes.......I will be getting quite a few plants in the near future and lots more fish so the water changes will start up again

[hevalump]

currently doing 30% change weekly, with the odd one between, recently set up tank (one month old this weekend) and am monitoring the nitrite levels religiously, we have a few fish in there and I am guessing its going through the last stage of cycling (?) as levels are around 0.1 - 0.3...... its not that much of a hassle, but ive got only one big and one liiitle tank, not zillions like some of you fanatics So maybe soon i my nitrites will be down to zero and I wont have to be so paranoid. Im using nitrazorb though, when i put it in my nitrites were 0.1 and i am sure the pink colouration is a fraction more towards 0.3 then it was.... i wonder if my nitrazorb is working or whether my levels would be mental without it.

[Ira]

Doc, if your nitrite levels are up to 100ppm your fish would be LOOONG dead. But, if your nitrate levels were that high, they'd just be feeling sick.

[Doc Holiday]

Sorry my mistake, have corrected it!! Always get the two mixed up. :roll:

[Interfecus]

Thanks guys . I thought I was being quite excessive but it seems that 25% per week is reasonably normal.

Thanks,

Interfecus

[Dark]

I have two types of tanks as far as water changes go:

Holding Tanks

I test the water daily and change it as necessary to keep the fish happy. The tanks are bare save some rocks and pipes to break up the boredom and give them a place to hide.

These are my quarrentine tanks, so They get dosed, and 100% water changes are not unheard of.

Setup tanks.

Because my interest is in Tropical Freshwater Planted tanks ('till Pies gets his claws into me) i have a lot of planted tanks, some with fish and some without. None of these tanks ever get water changes unless there is something wrong, but they get topped up a couple of times a year depending on the evapouration rate.

My theory is that 'it should all balance out' and i did manage to go a couple of years with 3 tanks and no test kits at all.

Having said that, it is probably good to mention that I add iron and other plant supplements to the tanks to keep the green things alive - keeps them doing their filtration, and in encourage worms snails and micro/mini-organisms to make homes because they all have their own part to play in the tank cycling.

I guess that it would be possible to get away with no water changes in a lesser-planted situation if one added some form of nitro absorber or remover to the system, as that seems to play a big part in the necessity for water changes.

And although i don't know the reality of it, my plants seem to do better (i measure them :oops: ) if i don't vacumme the 'fluff' off the bottom of the tank - observation only, if asked to guess i would have to say it is because plants are from the 60's and therefore like brown carpet.

Crazy idea:

Take two huge tanks, create a nifty flow system that allowed you to take water from one, pump it to the other then back into the first.

(add in a filter or something somewhere along the way, stick one on each side of a wall)

make one a huge tropical planted tank, the other an unplanted tank.

sounds like a rough idea for an instant excuse for two more tanks (not to mention the theoretical lack of water changes if one can filter the other)

[Ira]

Make the big planted tank a huge biofilter and throw a bunch of guppies in it to occasionally get their fry sucked into the main tank. Like a FW refugium.

[Wok]

I must admit that i only change the water in my tank when i see that the tails on my orandas begin to turn white. this is maybe 4-6 weeks. and when i do change i do about 75% This enables me to suck out all the crap in the pebbles.

I will fill it up and add in 3 tsp of salt and 6 squirts of AquaPlus. fish seem to find this ok. then again i do have lots of plants

[Interfecus]

Ira, with the rate that the guppies would breed you'd overload it and need to do frequent water changes within half a year! Even a huge planted tank couldn't keep up with it.

[Ira]

If they're breeding fast enough to overload it, you're not dumping enough of them into the main tank to be eaten.

[Dark]

My Ghost Knife (Cochlean) is developing a taste for baby guppies

Thanks Interfecus!