Water change and temperasure questions

[cowgirluntamed]

How much is too big of a degree change (with cooler water) for a 50% to 75% water change?

I am still prefiltering my water and now that it is going into fall. Nights will be getting cooler. The room the two trash cans are in will get colder. Right now when I do changes its only about 3 degrees difference. I was just wondering, how big is too big of a change that I should worry about it? U can either heat the tubs or the room as necessary.

Also, for those that had followed my prefiltering stuff before...I ended up taking out the carbon and ammonia neutralizer and just put a normal sponge in the filters for this. My plants started to go downhill when I was using those and I'm seeing a lot of new growth now that I stopped. So between my well water and whatever is in it and easy green twice a week plus some root tabs, seems to be the best. I'm still prefiltering mostly to let the pH settle from being so low to getting to its normal 8.2. Everything is working fine so far. I've been doing this for about a month now I think.

 

[Lunar Jetman]

I usually carry out 50-60% water changes every week and don't worry too much about the temperature. My fish seem to enjoy the colder water being added so unless you have any delicate fish it shouldn't be too much of an issue normally.

As autumn/winter creeps in I will probably revert to a couple of smaller changes each week, say 20-25% each time so that as the water temperature increases between the new and the old it's not so much of a shock to the fish.

You could also add a dash of hot water to your buckets so that it takes the edge off the temperature or consider something like the Python water changing system (or cheaper equivalent) which will connect to a mixer tap and you can regulate the temperature of the new water accordingly.

 

[seangee]

Agree. In numbers I am happy to let the temp drop from 25C to 18C (that's a 14F difference). All of the fish are fine with this and so are the RCS.

Like you I pre-filter my water so my temps rarely actually drop by that much because I let the water stand at room temp for a day or so before adding so I regularly add water that is 3-4C cooler (6-8F). I change 50-60% per week so the actual drop in the tank is 2-3C.

 

[NickAu]

Agree. In numbers I am happy to let the temp drop from 25C to 18C (that's a 14F difference). All of the fish are fine with this and so are the RCS.

Same here.

 

[cowgirluntamed]

I usually carry out 50-60% water changes every week and don't worry too much about the temperature. My fish seem to enjoy the colder water being added so unless you have any delicate fish it shouldn't be too much of an issue normally.

As autumn/winter creeps in I will probably revert to a couple of smaller changes each week, say 20-25% each time so that as the water temperature increases between the new and the old it's not so much of a shock to the fish.

You could also add a dash of hot water to your buckets so that it takes the edge off the temperature or consider something like the Python water changing system (or cheaper equivalent) which will connect to a mixer tap and you can regulate the temperature of the new water accordingly.

The Python is why I had to switch to prefiltering in the first place....my well water was coming straight out of the tap at around 6.5 or so...and then would shoot up to 8.2 which is the norm. A lot of newer fish died because of it, though they may have had other issues as well. But so far with what I've been doing, even new fish now seem to do perfectly well since the pH is now stable before it goes to the tank.

Agree. In numbers I am happy to let the temp drop from 25C to 18C (that's a 14F difference). All of the fish are fine with this and so are the RCS.

Like you I pre-filter my water so my temps rarely actually drop by that much because I let the water stand at room temp for a day or so before adding so I regularly add water that is 3-4C cooler (6-8F). I change 50-60% per week so the actual drop in the tank is 2-3C.

Thanks for the info! I fill my tubs with very warm water (tonight one reached around 90f). The other may 5 less than that as I always have some extra new water left after the water change. My room temperature is cool enought that after two days it drops down to 73 or so. My tanks are kept at 75-76. But...I know that room will be colder down when the days start getting colder. So I didn't want to over due it and stress the fish.

I have glowlight tetras, harlequin rasboras, peppered cories, a bristlenose pleco, 3 spot blue gourami, black neon tetras and some guppies and bunches of malaysian trumpet snails and ramshorn snails.

 

[AbbeysDad]

I have been pre-filtering water to remove nitrates from my well water. I used to preheat the water for 25-50% water changes, but lately I've just added room temp (~70F) degree water and all has been fine.
HOWEVER, the nitrates in my well water has decreased (to about ~5ppm) and this summer I setup an outdoor 110g stock tank. Instead of water changes, I added a pencil stream of water for 30 minutes twice a day straight from the outdoor cold water spigot.....and the fish did just fine!
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On my 60g I have recently been doing the WC directly from the kitchen sink. I indexed the hot/cold faucet with a sharpie for ~75-78F. I do see a lot of pearling suggesting high Co2, but my pH out of the tap is the same after it sets (pre-filtered).
(Note that I do have a trace of ammonia in the well water so I use Prime.)
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I don't think I've ever heard of such a dramatic change in pH as mentioned just by letting it set in tubs or barrels for a day or two.

 

[cowgirluntamed]

I have been pre-filtering water to remove nitrates from my well water. I used to preheat the water for 25-50% water changes, but lately I've just added room temp (~70F) degree water and all has been fine.
HOWEVER, the nitrates in my well water has decreased (to about ~5ppm) and this summer I setup an outdoor 110g stock tank. Instead of water changes, I added a pencil stream of water for 30 minutes twice a day straight from the outdoor cold water spigot.....and the fish did just fine!
------
On my 60g I have recently been doing the WC directly from the kitchen sink. I indexed the hot/cold faucet with a sharpie for ~75-78F. I do see a lot of pearling suggesting high Co2, but my pH out of the tap is the same after it sets (pre-filtered).
(Note that I do have a trace of ammonia in the well water so I use Prime.)
------
I don't think I've ever heard of such a dramatic change in pH as mentioned just by letting it set in tubs or barrels for a day or two.

I hadn't expected it either...so unless something changed in the well a bit...I don't know what to tell you. My family and I are still drinking it as well as the animals and everything is fine with us.

But the fish did stop dying as soon as I started letting it sit out...so...that's the only thing I can think of that would cause it.

I didn't use to do regular water changes when I used buckets....but when I did them the fish were always fine. I just don't know. Another difference is that was from the kitchen sink and the Python I'm doing from the bathroom, opposite ends of the house.

 

[Byron]

As others have noted, a change in water temperature is not usually problematic, but it cannot be extreme. Temperature drives fish metabolism, and even relatively small changes can cause issues. A gradual change of no more than three or four degrees over a 12-hour period is normal for most tropical waters, and many do not even get this much diurnally.