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Water Changes: Frequency


roo

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I have heard of people doing 2 X 50% water changes per week, and some do one 25% change every fortnight and many others somewhere in between.

Can you change the water too much? Or is is good to change water more often?

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I think people who do 100% waterchanges per week are simply beating the whole nitrogen cycle by not allowing any bacteria/ammoina/nitrites/nitrates to form. In this case, why have a filter? I think that it is far to excessive and alot of effort. Your better off doing the recomended maximum water change of 30-40% a week if you want to be very pedantic about your tanks or if you want your fry to grow faster.

Anthony

PS: Anyone feel free to disagree or correct me smile.gif

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I'd agree. I usually try to minimize the amount of water changes straight from the tap for some of my sensitive fish. For instance i might change 20-25 percent of the water in my demasoni or fry tanks each week, or sometimes twice a week.

On fish less sensitve to tap water mixed with conditioner, I do 30-35 percenmt changes easily each week.

If you have a better water changing regeme than i do -like aged water in barrels with no metals and chorine/choramine in it than you can get away with larger water changes on more sensitive fish.

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Yea i do the same Lepper, 35% fortnightly, sometimes i do it weekly depending on how i feel the tank is running or depending on wether i feel like it...lol

Anthony cool.gif

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slightly off topic, but what are some techniques people use to actually get the water back in the tank?

Changing 20% of the water in 250L tank is 50L, thats 5, 10L buckets. Now, what happens if you have 4 or 5 250L tanks?

How do you guys cope? what are your secrets?

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I do my water changes as follows ( i live in a unit)

1/ Siphon water from tank straight into the shower ( about 6-7meters away) I use a short bit of clear hose to start then slip it in side a long garden hose. Only spill a tiny bit.

2/ Fill up a 60 litre Garbage bin ( bought for water changes only)

3/ Stick 25mm hose in the tank and attach to manual bilge pump you can get for about 30 bucks at Whitworths, stick the the end in the bucket and pump

4/ takes me about 2 mins to pump 60 litres into the tank, and about 5 mins to drain it out ( smaller hose)

A friend of mine has a 500lt tank and we were just discussing altering this to suit his needs,

By placing a big blue drum ( 200lt) on wheels with the pump connected to the frame and attached to a skin fitting inside the drum. then all he has to do is wheel the thing next to the tank and stick the other end of the hose in the tank and start cranking. LOL.gif

PS Using a drum allows you to add water conditioner, heat it, ... whatever you like before you put it in.

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I do the same as roo except I siphon the water out of my tanks into a tub and then use an electric bilge pump I bought from whitworths smile.gif to pump it into the bath. It runs on 12V so I hooked it up to an old pc power supply unsure.gif

I then refil the tub from a hose connected to my washing machine taps.

Dean

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I add water conditioner to the tank then fill straight from the backyard hose. I've been doing it that way for a year with no issues yet...

Interesting..

I always thought u needed to add the conditioner to the water before adding to the tank.

How long does it take chlorine to kill off the bacteria?

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I think your all underestimating the resiliance of the bacterial colonies. The speed at which it can reproduce to meet influxes in loads, and also balance out quickly with a sharp drop in load.

I do 50% water changes, straight from the garden hose, every 3-4 days on fry tanks ideally, and if I skip it for a week or 2 because I am away or busy, there is no drama with spikes. The only thing that climbs sharply in my fry tanks with fully cycled filters is nitrates and poop. And this is what my water changes are there to reduce.

Changing 50% twice in a week certainly IS NOT equivalent to a single 100% water change in terms of shock to livestock and bacteria.

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I add water conditioner to the tank then fill straight from the backyard hose. I've been doing it that way for a year with no issues yet...

I always thought u needed to add the conditioner to the water before adding to the tank.

Just remember if you choose to employ this method, you MUST treat the WHOLE volume of the tank water with conditioner, not the amount your changing. thumb.gif

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Just remember if you choose to employ this method, you MUST treat the WHOLE volume of the tank water with conditioner, not the amount your changing. thumb.gif

Hmmm.. that could get expensive after a while.

What about your fry tanks then? Do you condition them?

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What about your fry tanks then? Do you condition them?

unsure.gif Of course. If I didn't, the chlorine in the water would knock my fry and my bacteria out in about 15 seconds flat (ok thats probably an exaggeration)

Remember like everything else, if you buy a bigger bottle of conditioner, the cost/dose ratio looks better for your pocket. There are also very potent water conditioners which might seem expensive per litre, but which treat 5-10x more than a standard conditioner so it is actually far far cheaper. I recommend PRIME for value for money, or SAFE if you do massive amounts of changes. Both are from SEACHEM.

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I only change about 15% weekly but I have 750L of tanks so I fill a 120L wheely bin located discreetly in the laundry after I do a change. I put some conditioner in this (for the chloramines). I have a heater and a small powerhead that circulates the water through the week. Next week, when it comes to water changes I have another powerhead in the bottom connected to a garden hose with a tap on the end that's coiled up above the bin. I simply flick the switch for the powerhead and walk about the house filling tanks. Works for me. (teamsherman can probably attest how bad of good it is as he has been changing water for me for a few months, what a buddy!).

Discus keepers often change enough water that the bacteria does not build up at all. Be it 50% a day or similarly large amounts of water regularly. It's not abnormal, according to my books and friends for discus tanks to have very small or no filter at all.

If you are very diligent (or have an auto changer) you can not do too much water replacement but you always run the risk of an ammonia spike. Just one small miss of water changes would be all it takes. That's not for me.

According to Tom barr it also helps if you have a highly planted tank, he does more than 50% weekly in highly planted and fish stocked tanks.

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I do 1/3 to ½ water changes weekly on my adult tanks, and 50% to 95% twice weekly on my grow out/fry tanks. I use water pre-conditioned (to increase pH and KH), heated, filtered, aerated and Safe (water ager) and pumped by a PM4200 straight to the tank/s. In the past when I have had greater fish loads (and I mean ABSOLUTELY huge), I have done 95% water changes every two days (which I did for many months). I do these water changes because of large fish numbers.

As Ducksta said,

I think your all underestimating the resiliance of the bacterial colonies. The speed at which it can reproduce to meet influxes in loads, and also balance out quickly with a sharp drop in load.
Believe me, the fish and bacteria can handle it. Bacteria are sensitive to the poisons in the water such as chlorine and chloramine, not to the changes levels of their food, which their population density will just match.

If I did a big water change after not touching the tank for several months, then I might expect to have an issue (with the fish, not bacteria), but doing large water changes and doing them regularly there are NO downsides apart from the labour involved.

Water changes remove nitrates, that the aerobic bacteria don’t touch. Incidently, there are other things in the water that water changes remove other than nitrates. If you built a successful nitrate filter, and your nitrates were always nil, you would still need to water change.

Craig

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Hi All

I am with Craig as I do similar to him. (He showed me all his secrets wink.gif ).

The only thing I have found is that I can loose condition on some of my small tanks that only have sponge filters.

This generally coinsides with a pumpkin feed for my BN in the variuos tanks so the pollution levels are generally up in the first place.

Similar small tanks that have AC300 filters don't have the same problem. Basically put it down to a good buffer of bacteria which the tanks with the spounge filters just don't have.

This doesn't happen after all water changes just some. I fix the problem by moving one of my canister filters onto the tank, problem fixed in a couple of hours. This canister is specially set up with long hoses to move it to a tank that needs extra filtraton.

hth

Andreas

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OK, i was under the impression that their was alot of the 'good bacteria' present in the water, there fore if you take most of the water out you will have problems?

From what you guys are saying, it doesn't matter, as there is still plenty of bacteria within your filter system to cope with large amounts of water being removed/replaced and what ever bacteria is removed, it is replaced very quickly by the bacteria reproducing it self. Is what i've said accurate to what you guys have been discussing? Just asking as i'm always willing to learn more about the nitrogen cycle and how it functions. It will help my understanding of how my tanks serve to keep my fish alive.

Anthony thumb.gif

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I'd just add one thing: note that Andreas and Craig condition and age their water before doing a waterchange. That way the water they're adding has roughly the same level of salts etc as the water they are removing and they don't get big swings in pH, gH or kH. if you did this with a waterchange via the garden hose you'd get some pretty wild swings in these parameters.

Some of the softer tanganyikans (for example) would find this pretty rough in which case you'd have to either match the water conditioning/aging regimes Craig & Az do or simply do smaller water changes from the hose as I do ('cos I have nowhere to hide the 2000 or 3000 litre water aging tank I'd need to match Craigs 1/3 to 1/2 waterchange ratio)

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OK, i was under the impression that their was alot of the 'good bacteria' present in the water, there fore if you take most of the water out you will have problems?

Aerobic bacteria needs three to live, oxygen, food (fish waste), and a surface (to attach to). There will surly be some bacteria that are floating about, but they will NOT be the ones doing the tank cycling. For the most part I would imagine that they are the “old fogies” not strong enough to hold onto a surface any longer, and have drifted off, soon to die.

From what you guys are saying, it doesn't matter, as there is still plenty of bacteria within your filter system to cope with large amounts of water being removed/replaced and what ever bacteria is removed, it is replaced very quickly by the bacteria reproducing it self. Is what i've said accurate to what you guys have been discussing?

Bacteria live on all surfaces within your tank, and filters (glass, rocks, gravel). The reason we have biological medias, is that a surface area is a limiting factor on the amount of bacteria that can exist in our closed systems. By putting in biological medias, we are vastly increasing the available living space. The amount of water we do or don’t remove, does not affect this living area. It will take out the amount of food available to them, but truly, you can’t take out enough to have impact on the bacteria, that will then have a flow on effect and have an impact on the tank/fish.

I’m not saying the bacteria are not important. In our fish tank, they are the heart. But they will easily cope with fluctuations in their food levels by simply expanding or contracting their populations. That is not to say if you have a large tank, with say two fish in it, then one day you put five hundred in there, you will not have a problem. In this case you will probably get an ammonia spike (dependant on the type biological media you use, for example a fluidised bed filter may handle this population increase). But what we are talking about with water changes, we have a stable fish population, and a relatively stable bacterial population – which will vary with their numbers to what ever their limiting factor is. If we do large regular water changes, then their available food will in fact remain fairly constant, and so will there numbers

And I would emphasise what Laurie has said, I prepare all my water before I use it. It makes water changing REALLY simple, and though a hassle to set up initially, once done and a routine is established to adjust water parameters, the advantages and peace of mind far out weigh any effort in maintaining it.

The only thing I have found is that I can loose condition on some of my small tanks that only have sponge filters.

This generally coinsides with a pumpkin feed for my BN in the variuos tanks so the pollution levels are generally up in the first place.

Similar small tanks that have AC300 filters don't have the same problem. Basically put it down to a good buffer of bacteria which the tanks with the spounge filters just don't have.

This doesn't happen after all water changes just some. I fix the problem by moving one of my canister filters onto the tank, problem fixed in a couple of hours. This canister is specially set up with long hoses to move it to a tank that needs extra filtraton.

Sponge filters, though they are able to cope with small amounts of small debris, their primary benefit, in my opinion, is as a surface for a bacterial colony. Provided one keeps the sponge clean, and cleaned in waste water from one of your tanks, one should have no issues with the water issues relating to the nitrite cycle. I have four ten litre tanks each with a small Tetra sponge filter in there. I water changed 95% in them just yesterday, the occupants, though cichlids, and thus relatively hardy, were fish only just old enough to have lost their egg sack. I have no problems with any of the fish. Some times, with large fish loads in these tanks, I have issue with large amounts of free floating gunk, a 95% water change takes most of this away, I then clean the sponge in the water from the tank it came from.

Craig

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