water change

[ghostsword]

doin 50% water changes is the way to go.. i dont have any tests either.. but been doin these water changes for 2yrs and never had any problems.. if i go on hols, i do a water change, dont dose with any ferts and my fish (not that they like it) can usually last 2 months if im gone for that long..also i usually get a friend to come feed my fish every 2nd day..

Hi.. If you don't dose with ferts for a month, do you also decrease the light period and CO2? I will be going away for a month and I am trying to figure out how to keep the planted tank going.

[Greystoke]

This reminds me to apologise to Nerville for hi-jacking his thread  

I do a carbon copy of Lauré’s procedure, except I do a 75% change (my remaining tanks are a bit overloaded).
The 75% change is due to the higher waste production as a result of the higher feeding rate (I keep track of the food dispensation and accordingly adapt the water changes).

This brings me to Tyrone’s input.
I’ve done this same exercise (and I can show the data), except I included other tests as well. The trouble with conductivity is that the dissolved elements have different contributions to the conductivity. Organic compounds contribute nearly nothing, whereas mineral salts have a much larger impact.
Fish food waste is probably mostly organic waste, with only some mineral waste.

Just think about it: All fish food must return to the water as waste. Therefore the water pollution is in direct proportion of the feed rate.

Cor

[Nerville]

This reminds me to apologise to Nerville for hi-jacking his thread 

no problem its a good discussion.

I do water changes at random intervals and random quantities. Maybe i am lazy. 
just wondered cos after testing everything still seemed fine.

tank is not heavily stocked though... it is however heavily planted.

[shihr]

hey gohstsword, no, the co2 and lights r like normal so the plants can suck up any extra waste:) the bennificial bacteria in the filter converts amonia to nitrites and then to nitrates and ur plants suck that up.. ppl correct me if im worng

[Greystoke]

For those who are interested:
These are the test results I kept of an unplanted versus a heavily planted tank with a 100 female guppy population.
The plants were vallis grown in trays.

test-blog

[tyronegenade]

What is your substrate? Are you adding shell grit or coral chips to the tank?

The data shows a nice trend between fish food and N (which is what one would expect).

[Greystoke]

What is your substrate? Are you adding shell grit or coral chips to the tank?//

No substrate Tyrone. I tried shell grit, but I found it very ineffective. I used a lot of sodium bicarb to maintain the pH.
The tank was empty when I started the test, then - after a week - I put-in the trays of vallis, and redid the tests for two weeks.
The last week, the vallis flowered, which would explain the increased use of phosphates in proportion to the nitrates.

Regards
Cor