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Water change question/opinions

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I am an experienced fish keeper (successful at planted tanks, always low tech), but there are always times when it seems like I could learn something more or maybe I am missing something.

With my fish load 30% water changes per week keep my tank going great. Whats better, 10% water changes thrice a week or a 30% water change once a week?

CO2: none, no Excel
Substrate: river sand+commercial high CEC sub
Ferts: liquid + root tabs


Thanks.
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It may seem like overkill to some, but if you do a couple of small water changes that are really just part of a maintenance routine, and a 30% once a week, you'll probably see fewer problems than most. Some of the tanks that I keep in the fish room really dictate that sort of schedule.

So that's 10 + 10 +30.

The math is getting intense!

But in the end, I have to agree with Ichy. Stick with what works for your set of circumstances. Pair that with a keen sense observation to catch things before they get out of hand, and you've got your answer.
 

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Discussion Starter · #7 ·
Thanks everyone. I read the other thread posted by Mario as well.

I have read 2 contradictory things at multiple sites:

1. in a very low tech tank, dont do too many water changes as you are then removing the nutrients the plants could benefit from
2. large water changes (minimum 50% per week?) contribute to great plant health

me confused :) . what is it exactly? I guess ultimately you are to figure out what works best for your tank and conditions.

I am going to give 30% x 1 time a week a shot.
 

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Its all about changing enough water to ensure you are maintaining the levels you want.

The first thing to consider is the amount of stock. This means in heavily stocked tanks you are going to need larger water changes to ensure nitrates don't build up.

We don't really think about removing nutrients as being part of the water change because generally we will be dosing our tanks. Also, consider that a WC will bring replenished minerals and remove organics. All good things.
 

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Thanks everyone. I read the other thread posted by Mario as well.

I have read 2 contradictory things at multiple sites:

1. in a very low tech tank, dont do too many water changes as you are then removing the nutrients the plants could benefit from
2. large water changes (minimum 50% per week?) contribute to great plant health

me confused :) . what is it exactly? I guess ultimately you are to figure out what works best for your tank and conditions.

I am going to give 30% x 1 time a week a shot.
Yep lots of contradiction to that affect. You have to consider the environment of your tank and draw your own conclusion. My 75 gal is just over a year and no water change was ever done. Plants, fishes, snail and shrimps are happy. The amazon sword that I planted 6 months ago went from about 5 inches to over 20 inches.
 

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I think ultimately, the answer depends on what sort of tank you have - a planted tank with a few fish, or a fish tank with a few plants. If it's the former, you can get away with fewer/no water changes, if it's the latter, it's not a good idea.
 

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I think part of the contradiction comes from different styles of low-tech tanking... ie: how low-tech do you consider to be "low tech".

I do 50% weekly water changes... however I also dose fertilizers in a modified EI low-light dosing scheme... Since I'm adding KNO3, KH2PO4, K2SO4, CSM+B and DPTA Fe to my tank on a regular basis, the loss of nutrients from the water change is irrelevant. Some folks call this low-tech because I'm not dosing CO2.. others call it medium tech because I dose fertilizers and use glutaraldehyde.

However, a very low-tech tank with no dosing would suffer a loss of fertilizers with a heavy water change schedule.. Such tanks are heavily dependent on fish waste for nitrate/phosphate.

Unfortunately, there's a lot of terms for "ranges of thing" in aquariums with no hard-fast definitions.. low/medium/high tech, low/medium/high light, lightly/moderately/heavily stocked, lightly/moderately/heavily planted, all of these terms have somewhat flexible definitions that vary from person to person.

Often this results using different criteria for the same term. Some folks (ie: hoppy) call 50 par high light based on the need for CO2 injection and HC readily carpets with enough CO2. Some folks consider 50 PAR too low to call high light, as most red plants don't show their best colors, and favor numbers around 80 as a minimum...
 

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If it works for you (You can handle the water changes frequency and volume) and it works for the tank (thriving fish and plants) then run it that way.

If you want to get into the chemistry of why it works, that can be interesting research, but will keep coming back to the original concept:
Do what works for you and your tanks.

If something is not working, the change something else until it is working.
 

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Water Changes

Hello ad...

Half the tank water should be removed and replaced weekly. If you have a tank under 20 gallons, then this should be done twice weekly. Here's why: Water that constantly moves through a filter, looses minerals needed to support fish and plants. Everything in the tank dissolves to some extent and this material pollutes the water.

So, no matter how many fish and plants you keep, you should still be replacing at least half the tank water weekly. I'd recommend more than that, because the more water changed and more freqently, the better the environment for anything in the tank.

Pretty simple. It's all about the water.

B
 
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