UV and liquid ferts

[Allen_1971]

In the past I've asked on various forums about the effects of using UV in a planted tank, and I've not been able to get a good answer on wherther it has an impact on the tank.

Recently though, my tank suffered a complete collapse of my biological filter (which is another story) resulting in a massive bacterial bloom (so white you couldn't see the back of the tank). After trying all sorts of stuff (for about 2 weeks), I decided to wipe out any water bourne bacteria using UV filters. And it worked... within 2 days, my water cleared.

On the advise of others, I left the UV filter running for another 2 weeks. One thing I noted during this period of time was that some of my plants in particular my H.difformis and H.corymbosa were shedding lots of leaves... however I didn't think much of it. Then came the shocker... My tank is usually N deficient... so much so that I dose KNO3 to alleviate any nutrient deficiency. When I measured my NO3 levels, they were a whopping 25ppm which is a lot considering I usually leave it at 5-10ppm. What dawned on me then is that something else had become a limiting nutrient in my tank allowing the NO3 to begin to accumulate. This suspicion was further verified by poor plant growth, and in the worse case, my h.corymbosa suffered stem rot.

My immediate suspicion fell on the UV lamps... My main weekly fertilizer is a liquid fert (TMG), and sometimes I supplement traces as well which is also liquid... all of which would get hammered by the UV light. So as part of an experiment, I switched off the UV lamps, did a water change, and redosed my TMG. The result was almost instantaneous... that evening my plants were bubbling like crazy... even more than before.... looks like a period of "starvation" made them more "hungry". Since then also, my NO2 levels have been on the decline again... and should go back to my normal levels by next week.

Anyway, for those of you with planted tanks, I would strongly advise against using UV... especially if you primarily use liquid ferts.

[cks]

Allen
May be this may be the answer to your problems !

For super cleaning your aquarium and water polishing, the "Diatom" is a high-speed filter designed to filter aquarium water to an extremely pure state, without disturbing the natural bacteria levels.

Vortex Diatom Canister Filter
For super cleaning your aquarium and water polishing, the "Diatom" is a high-speed filter designed to filter aquarium water to an extremely pure state, without disturbing the natural bacteria levels.
It uses a unique diatom powder to filter particles as small as one diatom in size. Even some parasites and bacteria are large enough to be trapped and pulled out of the water by a diatom filter.


Used properly, your Diatom filter will eliminate the need to "tear down" your aquarium to clean.


Model D-1 is for most routine cleaning jobs.
The Diatom XL, which filters at up to 300 GPH, is the highest speed aquarium filter on the market (designed for continuous operation).


Features:
Electrical on-off switch and self priming motor
100% filtration of water that passes through the pump - no hidden "by-pass holes"
Self-contained and designed for continuous operation
Quiet operation. Thermally protected motor
Adjustable and directional flow
Backwashes clean without taking the filter apart
Protected against gravel jam of the impeller
Motor shaft is connected directly to the impeller (no slipping magnetic drive or squealing belts)
Easily recharged with filter media - Diatom filter powder, superchar or water softener may be added while the filter is running.
Positively does not change pH
New unbreakable chamber base stand and jar!

[Allen_1971]

CKS,

thanks, I've read about diatom filters, and they sound like really great devices... however, I've never seen these on sale in Singapore... and also, due to the means by which diatom filters work, the filter needs to be replaced often which leads to high running costs...

All in all I'd rather just stick with normal filtration and healthy plants

[BFG]

CKS do u have pics of the said item?

[David]

Hi Allen

well at least you got rid of the bact bloom[]

Think the situation in your case is that the UV filters are turned on 24/7 which is the quickest way to get rid of green water and bact bloom. However on a preventive measure, it only needs to be turned on for 4 to 6hrs depending on the filter it is attached to and the wattage of the bulb. There is actually a calculation table in the instruction manual...but I am too lazy to work the maths.

When turned on, its best to work it during lights off period rather then lights on. fertilisation should not be exercised in week (7 days) block but rather on 3 day dosing (best is daily).

Dosing should be done at the beginning of the lights on period so that whatever needs to be absord by the plants would have been taken before the UV rays destroys it.

[DEA]

ahaz.

anyway, instead of playing with high tech toys, think about using filter floss (just compact it) and maybe a flocculant (like interpet filter aid)

[Allen_1971]

Been there done that... didn't work in my case... bought seachem clarity and dosed it... but no my water didn't clear at all... even after a few days...

[FC]

I had shared a few times before about my very bad experience with cloudy water. And I always beleive UV light is the most effective tool for getting clear water again. As I said before, now that Allen also experienced, that I had tried nearly all methods but failed.

Yes, David mentioned a good point about the timing of UV light and fertilisation. I did the same and it worked beautifully.

[Allen_1971]

I'm still a bit skeptical that using UV on a timer at night will be any different... Reason I think so is this... Our filter rates are usually about 2 times our tank capacity... so even within the hour, our water would cycle through the UV lamp twice. So even if you leave it for just a few hours, theres more than ample opportunity for the ferts to be blasted by the UV and broken down... Unless you are saying that when the UV is off, the ferts somehow recombine back to more usable states? Perhaps someone with more chemistry background can comment...

[David]

errrh allen...not really, through the course of the photo-period, plants will only absorbs what it needs during this time-frame and no more... if Kasselmann is correct, the plants will then extract norishment from the roots....

If you noticed in my last posting, daily dosage of liquid fert would be the best......