Longer water change frequency and fertilisation

[juggler]

Due to time constraint, I am doing my water changes once per 2 or 3 weeks.

It looks like the plants are not growing as nicely as before. This has been going on for about 3 months. No algae problem though.

I am still adding fertilisers daily and weekly in the same amounts as if there's 50% weekly water change. I have not tested the water.

Question is: Is dosing at the same rate causing the nutrients to reach toxic levels? Should I be dosing less? How much less?

Anyone doing such a routine can share? Thanks.

[PeterGwee]

Buildup to toxic levels is highly unlikely since the water change will still come in 2-3 weeks time. The likely culprit that I can pin-point is perharps the CO2(check and recheck) and NO3 (I know you did not dose much or not at all? The tap might contain the NO3 that your plants are waiting for and hence the poor growth when you do not do it.) Maybe you can try dosing some KNO3 but in relatively smaller amount since your water change is only every 2-3 weeks once. *(Do larger water changes like 60-80% if you do it every 2-3 weeks to clean up the excess.)

Regards
Peter Gwee

[juggler]

OK. I can try some NO3 and see how.

Anyway, the daily feeding is same as per normal at 1/2 tsp Tetra Bits twice plus 2 cubes of bloodworms for the 5ft tank.

[Sleepy_lancs]

Maybe is Chemical Warfare between the plants. Water change help relieve that.

[barmby]

No weekly water change and yet no algae. It seem like NO3 is depleted. Pay more attention to CO2 and plants once you start NO3 addition.

[Plantbrain]

If you want to have less water changes etc, try less light. This helps a lot.

Water changes re set the tank's nutrient levels. This is an easy to use method that requires no testing. The longer you go without testing/water changes, the more unknow things will be.

Maybe you'll get lucky, maybe you'll know when you can go no longer etc by plant health. But you start guessing more and more.

If you want a low maintenance tank, non CO2 are great. I keep 2 and 2 CO2 high light tanks. Less light will also slow the growth rate down also.

This way you can get more out of the fish waste to supply the nutrients, less demand on the tank in general when using CO2. Less light is a very nice approach and gives you more wiggle room with routines/tank neglect.

1.5-2w/gal is pretty good.

Regards,
Tom Barr