How much water to change?

[voodoo]

Need help! Need to know how much water can we change before cosing stress to fish and plant. Or i can simply change the whole 4feet tank's water? Reason to change = NO3 <40mg/l. If i can change the water to around NO3 10-15 mg/l, will that mean that Fe and the other micro nutrient will be way below optimum? i m using LG-AQUA, it contian N, does that also means that i cant use it to dose to get micro up after the water change?

4 feet tank
6x36w pl
all parameter ok cept NO3
pressured CO2
medium planted
fish load 10 rasbora ,15 neons, 6 yamato, 4 SAE

Not the tank in my link, new 4 feet tank.

[David]

Errrhh how old is this setup anyway.....I would think that changing 100% of the water is not a good idea.....even 50% at one go is not advisable.....it may be a better idea to change, perhaps 30% of the water every 2 to 3 days.

At the meantime it may be good to stop all fertilisation, and you need to find the root cause of your high NO3 as it seems that your bioload is not that high.

[voodoo]

Thanks David.

The tank is 1 year old. 3 weeks ago, pulled out all the plant , fill with water and let it sit for 1 week before planting. Come to that, i suspect its the ramnant roots rooting that causes the high NO3(just thot of this when changing water last nite). Any way, i changed 40% of the water over the course of 5 hour. hope it did minimum stress to living thing inside(better then dying). This morning wake up, fishes seems ok, NO3 is around 10<15mg/l. Hope it wont go up.

Any one got experince with ramnant root rooting that couses high NO3? How u go about balancing it? thanks.

[juggler]

Test kits tend to be inaccurate. Eg. When I used a new Sera NO3 test, it gave me higher NO3 reading than an old kit.

If there's no algae problem so far, just keep monitoring and maintin your fertilisation. Lushgro-Aqua has NO3 but it is not significantly high unless you dose a lot.

[voodoo]

Hi juggler,

Bingo! sera NO3 test kit! the 1 i m using. But could it be my tap water? tested to be 10mg/l. Maybe buy other brand to test. No algae at the moment, some algae on the glass but dont seems to be growing. They r my indication for water nutrient