Analyse This!

[geoffrey]

Hi All,

I like to share this observation I made on my 2ft. It has two 36W PL shining on mostly E. tenellus; C. wendtii and balansae; E.parviflorus and Nanas. Happy is a family of 3 rams, 1 apisto, 25 cardinals and green neons, and an unknown population of snails and shrimps. Note, big fish load for a circa 70 litres tank.

The usual routine for my happier times was weekly water change of 50%. Afterwhich a dose of 18ppm of NO3 and 11ppm of K from KNO3, 1ppm of PO4, and 10ml of Easylife Profito. Mid week, another similiar dose of everything mentioned. Life was indeed easy with no algae, not even a speck of green on my tank walls and no trimming.

My hands itch. Altered water change regime to fortnightly at 50%. Fertilising dosage maintain. One dose after water change and 3 more doses spread evenly over the 2 weeks before the next change. And what do I get? Very slowly but surely, algae begin to appear. It starts from the tank wall, green spots, follow by BBA then recently some BGA.

What do you guys think? My hunch is NH4 buildup to a new equilibrium with the longer water change, big fish load, remember? And this tiny new increase in level is enough to sustain an algae outbreak. BTW, I forget to say I have good CO2.

I shall be going back to weekly water change. I want my happier days back!

[PeterGwee]

Geoffrey, that is one heck a lot of critters in a small tank! You are better off doing 2x a week 50% water changes if you are having issues so as to whip the tank back into shape before reverting back to perharps once a week 50-70% water change. How sure are you of your CO2 levels? I know you are doing 24/7 with the CO2 and I have done it personally. The CO2 levels tend to be chronically low down to 10ppm at the end of the cycle so as to avoid an overdose during the night. Not a good method in my opinion and that is properly why the BBA broke out. Do a good review of your CO2 by checking the pH both in the am and pm times before lights on and off for the entire week. If things seems fine and within range, add a touch more CO2 incremently till you get the plant growth you know you should have but monitor for abnormal critter behaviour. The BBA should stop growing if your CO2 is indeed high and good. (I have seen it with my personal experience..) The BGA seems from bottoming out of NO3. The 18ppm of NO3 that you are dosing per week was enough but properly bottom out when you decide to stretch it to two weeks. You can add more like 2x the amount you are currently doing but the issue with not doing large water changes will make potential buildup of nutrients more serious if you overdose.

Regards
Peter Gwee

[geoffrey]

Peter, I am doing 36ppm of NO3 per week :P not 18ppm but 18ppm twice per week. Hence, total NO3 before each fortnight water change is 72ppm :P and feeding is generous too.

Yeah, I just let my CO2 runs 24/7 but it was fine before. Anyway, I am reverting to weekly 50% to manage the NH4.

But I am itching to fiddle with PO4 to help accelerate growth. Maybe by another 1ppm per week. I am hoping the faster growth will help uptake the excess NH4. How?