The Planted Tank Forum banner
1 - 20 of 29 Posts

·
Registered
Joined
·
595 Posts
Discussion Starter · #1 ·
Why should you not do 90% water changes?

Why does it max out at 50% ?

Temperature differences, ammonia generated from Chlorinates, etc...?

Thanks
 

·
Registered
Joined
·
146 Posts
If you can control your parameters down to a .00 than go for it. I do big ones every so often. You just don't want to shock the system. I mix ro and tap, monitor tds and I've never had an issue. I do not exceed 70% though, do not see any point in going beyond. Honestly, only reason I ever go beyond 50% is I'm trying to siphon out all the little trimmings and cracking kicked up in the cleaning.
 

·
Registered
Joined
·
5,576 Posts
If 90% of the water is changed from the beginning, then little issues with fauna.
Same for 50%.
Is when sudden large changes outside the norm happen, that larger changes in water chemistry (ie) GH,pH, can have negative effect on fauna.
Some Discus purist's change 80 to 90 % of their water three times a week and fishes grow large and sassy.
Much of this I think, is due to several feeding's a day in order for the fishes to reach full growth potential.
This amount of organic matter entering the system daily, and resulting fish waste(poo) would quickly foul the water .
I have often heard folk's suggest that 50 % water changes each week with say EI method of dosing is to reset nutrient level's ,but more so I believe, and according to true guru's, to remove not only what fishes might create, but to remove protein's and or other matter that plant's respire or don't use = less available for algae.
Coming from fish only side of the hobby, 50 % water changes each week is better than fewer or smaller %, for it removes more of what you don't want in the tank and water chemistry will not drift too far from source water unless one is taking measures to alter it.
Regular large water changes have many benefit's.
90 % however would not be needed in my view under moderately maintained aquarium's.
Opinion's vary.
 

·
Banned
Joined
·
6,196 Posts
I change about 75% of my water every week. Have for decades. Fish and plants seem to love the water change, and to me it's one of the cornerstones of long lived fish, along with heavy filtration and good surface agitation. In any event, I respect all opinions but it's always worked for me.
 

·
Registered
Joined
·
2,945 Posts
When I had bettas in bowls I did 80-90% wc every week. But now that I have bigger tanks that are much more stable, that would seem overkill to me, unless I had done replanting and stirred up a crapload of mulm. I do 50% now. More would be quite a bit of work, especially as I'm still hauling five gallon buckets thru two rooms to do it!
 

·
Registered
Joined
·
474 Posts
I think it depends a lot on how different the changed water is from what the fish are living in. If you're doing 90% every month, that's a bigger shock than 90% every day.

No point in spending obsessive hours acclimating them from the store only to subject them to massive swings in water parameters with each water change. Most people don't drip in the water for water changes, for example.
 

·
Registered
Joined
·
1,916 Posts
No rule saying you cant do 90% water changes. There is no maximum number.....you could do multiple 100% water changes in a day if you felt the need to. 50% is common as its large enough to take care of most issues but doesn't take as long as doing a bigger change. You have to find what works for you. Some people choose to do far less than 50% changes and have success and some choose to do much more!
 
  • Like
Reactions: Meexpec and Hoppy

·
Banned
Joined
·
6,196 Posts
I do 50% now. More would be quite a bit of work, especially as I'm still hauling five gallon buckets thru two rooms to do it!
Taking the time to streamline water changes is well worth the effort. I have a long hose and use a pump to empty, tap water to fill. And the laundry room sink is about 35' away. Got it pretty much down to a science now.

Once you get it more automated, it's no more work to change more water. And for me, it's much easier to stay on a regular schedule if it's easier.

And believe me, I do remember the days many years ago of lugging around 5 gallon buckets. You are a dedicated fish keeper to keep doing so!
 

·
Pixel Prestidigitator
Joined
·
4,343 Posts
One of the breeders here does 100% changes in all 50 tanks every week. If I had the time I'd do 90% changes in most of my tanks. Especially the fry tanks. I've found large water changes speeds up fry growth.
 

·
Registered
Joined
·
2,862 Posts
You can do large water changes without any negative effect as long as water chemistry/parameters stay stable throughout the change. Of course you want to mind not stressing the fish out so much just from the act of the water change (you and the siphon's presence and lowering water levels).
So take note of water parameters currently/going out and water parameters going in, they should be very close to cause minimal stress load on the fish. Note if water changes are done infrequently or whatever reasons cause water parameters to change quickly so that new fresh water may have a significantly different set of parameters. The more change/difference, the more load/work/stress that puts on the fish to adapt to.
 

·
Banned
Joined
·
5,942 Posts
The 50% covers probably the 90% of most planted tanks. They'll always be setups to the left of and right that would require less or more, like a bell curve. There's a wide variety of setups that can be maintained based on light, stock, plant mass, it's just a matter of how much maintenance and energy you want to put toward it.
 

·
Pixel Prestidigitator
Joined
·
4,343 Posts
You can do large water changes without any negative effect as long as water chemistry/parameters stay stable throughout the change. Of course you want to mind not stressing the fish out so much just from the act of the water change (you and the siphon's presence and lowering water levels).
So take note of water parameters currently/going out and water parameters going in, they should be very close to cause minimal stress load on the fish. Note if water changes are done infrequently or whatever reasons cause water parameters to change quickly so that new fresh water may have a significantly different set of parameters. The more change/difference, the more load/work/stress that puts on the fish to adapt to.
If your fish are used to large changes than it really doesn't matter as much if the parameters are off a bit.

The farms down here where a ton of fish come from will run the pumps all night long during spells of colder weather. The get a 100% change every couple of hours. It's been my experience we underestimate the hardiness of most (and I stress most) fish. Many of the fish are put out in concrete vats (burial vaults) to grow out. Some of the fish we get into the US spend days without filtration or any water changes and are in 1-2" of water. Then they are dumped into a cleaner environment where the parameters are more than likely a lot different than that bag water. And surprisingly they make it none the worse for wear.
Sure. You've got your more sensitive fish that need TLC for a while. But they do make the journey.
 

·
Registered
Joined
·
21,012 Posts
I routinely do 40-50% water changes, usually every 2 weeks, but if I need to shift the position of the tank a bit, I do about a 90% change to make it easier to do. Or, if I want to change something big in the tank, like hardscape or substrate, I do a 90% change, to make that easier to do. I can't recall ever seeing the fish react badly to that size change, and if anything they are more active and busy trying to breed immediately after. The magic 50% water change was chosen because it limits the concentration of anything you routinely add to the water to twice what you add between water changes. That fit very well in the EI dosing scheme.
 

·
Registered
Joined
·
595 Posts
Discussion Starter · #14 ·
When I had bettas in bowls I did 80-90% wc every week. But now that I have bigger tanks that are much more stable, that would seem overkill to me, unless I had done replanting and stirred up a crapload of mulm. I do 50% now. More would be quite a bit of work, especially as I'm still hauling five gallon buckets thru two rooms to do it!
I got a 20 gallon brute trashcan(made from plastic) with a pump attached to a white freshwater drinking hose. I fill up the aquarium, treat the water with prime and with a digital thermometer ensure the temperature is the same.
 

·
Registered
Joined
·
1,261 Posts
I've noticed with my tanks that pH goes up as the water matures. I start out low, about 6.2, and by the end of the week it is at 7.4 sometimes. I don't have substrate or filters, just floating plants and stem plants held down with one or two metamorphic quartzite type rock commonly found here in Virginia. If that can happen without much influence, then substrate and filters, etc., can have an effect on chemistry even more so. If you have high pH, and drop it quickly, it could be detrimental to the fish. So depending on your setup and fish and starting water chemistry, you can afford to do 90% or just 50% weekly without damage. I mostly just add water that evaporates and do a 25% water change monthly since I have floating plants do the filtering, and my pH, etc., doesn't swing so wide that my fish are hurt. Oh, and my water doesn't contain Chloramines. That makes a BIG difference from what I understand.
 

·
Registered
Joined
·
595 Posts
Discussion Starter · #16 ·
I've noticed with my tanks that pH goes up as the water matures. I start out low, about 6.2, and by the end of the week it is at 7.4 sometimes. I don't have substrate or filters, just floating plants and stem plants held down with one or two metamorphic quartzite type rock commonly found here in Virginia. If that can happen without much influence, then substrate and filters, etc., can have an effect on chemistry even more so. If you have high pH, and drop it quickly, it could be detrimental to the fish. So depending on your setup and fish and starting water chemistry, you can afford to do 90% or just 50% weekly without damage. I mostly just add water that evaporates and do a 25% water change monthly since I have floating plants do the filtering, and my pH, etc., doesn't swing so wide that my fish are hurt. Oh, and my water doesn't contain Chloramines. That makes a BIG difference from what I understand.
Yeah, Chloramines is ammonia and Chlorine(both deadly combination to fish). The tap water conditioner can neutralize the chlorine however the ammonia is left over.

Certain companies like Prime can do something with the ionization to make it not dangerous for like 24-48 hours. So you better have a good biological filter because you are left with a ticking time bomb.

You are very lucky that your city does not use chloramines.

So this is a big concern if you use a tap water conditioner which does not address the resulting ammonia.

So if the tap water has.
1. Same temperature
2. Same PH
3. water condition to handle the chloramines and resulting ammonia.
4. Same water hardness.

Then you could do larger water changes?
 

·
Registered
Joined
·
1,261 Posts
So if the tap water has.
1. Same temperature
2. Same PH
3. water condition to handle the chloramines and resulting ammonia.
4. Same water hardness.

Then you could do larger water changes?
It depends again on how much your aquarium water changes over the week. It does change, the question is how much and in what way. But theoretically, yes, if your tap water matches your aquarium water after a week, you can change it all! In my experience, that has never been the case. For example: I use my well water for 8 months out of the year (warm weather hoses to house) which is at the very low 5.8 pH often. My tanks may be at a constant 7.4 pH. So, smaller water change is necessary not to shock fish. I use my House water 4 months out of the year, County Water, at a pH of 7.2 or 7.4 on average, so I can easily do a 100% water change if I've had enough coffee that morning, without worry.
 

·
Registered
Joined
·
373 Posts
Personally my tap water parameter swing wildly one week to the next. I have seen 30 TDS one week, 200 TDS the next. So a big 90% water change would do more harm than good. So the most I would do is 50%. And I would refill super slowly over 30mins to give livestock time to adjust.
 

·
Registered
Joined
·
1,261 Posts
Personally my tap water parameter swing wildly one week to the next. I have seen 30 TDS one week, 200 TDS the next. So a big 90% water change would do more harm than good. So the most I would do is 50%. And I would refill super slowly over 30mins to give livestock time to adjust.
If there is a storm water issue, my County water can really swing as well. In the mid summer doldrums, the water reservoir can get nasty, and chloramines are possibly added if high bacterial count cannot be handled by chlorine. I've smelled the chlorine from the tap in those times. Luckily, I use the well in summer.
 

·
Registered
Joined
·
5,576 Posts
If I had source water that swung wildly from the tap from week to week,I would store water in large tub for water changes which I could use or alter, to what is needed.
Most are lucky enough to have consistent source water from treatment plant's with exception of possible flushing of lines annually when more chlorine is used.
Consistency for most, can easily be achieved with 50% weekly water changes .
Been doin it for forty year's.
 
1 - 20 of 29 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top