Water Changes?

[PikeLee]

I keep reading in many posts and web articles that 50% water changes are ideal a week for Planted tanks.

From my understanding, Plants help filter the water and suck up nutrients and waste. The lack of nutrients is provided by ferts. So my question is, and I hope it isn't a dumb one :rolleyes: , why are water changes so important in a planted aquarium?

[Faramir]

To the best of my understanding, it's partly because some trace minerals are in the tap water, and you are replenishing them by doing the changes. It is also to maintain KH - particularly important if you are injecting CO2.

I may be completely wrong, but that's what I've been given to understand.

[Plantbrains]

Well would you like to test for 4-10 or so nutrients and dose precise amounts each time you need to dose?

Or would rather guess once or twice mid week and re set the tank with a water change weekly?

By doing this you can keep enough nutrients in the water without ever running out for more than a day or so.

No nutrient builds up too high since you do large frequent weekly water changes and nothing gets too low since you dose nutrients every 2-3 days.

The bottom line is that it maintains a relatively constant range of nutrients. Less unknowns and less dependence on test kits.

You can do it "naturally" with fish, no CO2 etc but the plants grow much better with CO2 etc. They also need more nutrients when using CO2 than can be supplied by fish waste etc.

Using inorganic nutrients, like KNO3, KH2PO4, K2SO4, trace iron mixes etc also you to control and dose pretty easily the needs of the plants.

These are cheap. Regular maintenace is the best thing for any aquarist keeping fish. Too many folks try and slack on water changes. I have not needed to use a medications nor lost a fish in 15 years. Very simple things like water changes do a world of good.

All the technology in the world cannot make up for basic mainteance.

See the "estimative index" on the DFW plant club site for more info.

Regards,
Tom Barr

[PikeLee]

The reason for my question is because the PH from my tap is kind of high and the water is slightly hard. So large water changes can change the chemistry of my tank quite a bit.

I always thought that all the nutrients and all were being put back in from the ferts. I didn’t realize there were more elements that involved.

Regardless, I will increase my water changes and see how things work out. Thanks for the advice guys.

BTW,

Tom,
I totally see what you’re talking about with more light and no CO2. My 30g have 3.2 w/g. My Hagen CO2 ran out and I started to notice my water getting a tint of green from a side profile, plus some hair algae popping up. :( You weren’t kidding.

I didn’t get a chance to check out that site yet. I looked it up, but wasn’t able to reach it. Not sure if it was the jobs firewall or what. Anyways. Thanks again.

Cheers.

[Plantbrains]

By doing water changes:
This prevents build up of excess nutirents and any dosing errors.
By doing, you prevent deficiencies when done at regular intervals.

You basically re set the tank weekly and guess once or twice with a mid week dose or two. Test kits are often incorrect etc. Folks hate testing away. CO2 you cannot get away from but a maintained CO2 system or a gas set up makes this a non issue typically. CO2 is always the first place to check.
Regards,
Tom Barr

[PikeLee]

I really wasn’t sure on doing that big of a water change. I always thought if I did that much of a water change that my PH would jump up (Tap is 7.9, and the tank was 6.5).

I got a case of green water. It wasn’t bad at first, so I just did a 20%. I tested the water before and after. The PH stayed the same.

I did a search to get rid of the GW and read to do a 50% water change then a black for 2-4 days (CO2 was disconnected and the aeration was put on for 2 hours/3x times a day). I tested the water before and after the 50% water change, and the ph didn’t even change that much. To be honest with you, it kind of looked the same. I had a PH of 6.5 and a KH of 3 dkh.:cool:

Hopefully this will be consistent when I do my future water changes so I can go along with your recommended maintenance. This is my 1st planted tank, and I’m the type of person that has to learn things on his own. :rolleyes: Even after given advice. After that GW, I’m definitely going with the Advice.

Cheers.