UV causing ammonia spike...

[DIY]

OK, this has me scratching my head slightly.

I had an ammonia spike just over 2 weeks ago, in the 3 or 4 days just prior to that I had treated with food medicated with Levimsole and then Prazi (not at same time 2 days gap with W/C in between) I also had changed my purigen with some freshly regenerated Purigen bags. At some point in that 3-4 day period I had also turned on my UV light.

After 5 days of conescutive 200+ litre water changes the ammonia wasn't really reducing and I thought I must have completely killed my biofilter .I turned off my UV light in the hope it might speed up recovery by allowing any waterbound nitrifying bacteria to multiply. Next evening after turning off my UV, the ammonia had dropped significantly to the point of barely there, by the next evening - all gone.

Two weeks have passed and saturday again tested negative for ammonia, been testing almost every day as I've been paranoid about ammonia for last two weeks. I turned on my UV again yesterday and tonight I tested positive for ammonia again - another spike!

I understood nitrifying bacteria are are everywhere in an aquarium, gravel glass, water, filter pad, bio media etc but it almost seems like I only have the good bacteria in my water..

Never had a problem using my UV before now though - any ideas?

[Merrilyn]

Doesn't seem possible, does it.

You're right, the nitrifying bacteria is on all the solid surfaces in your tank. Very little is in the water.

Just a thought, is the uv connected to the intake or outlet of your filter, and what's the distance between the uv and the filter.

Hmmmmm :scratch

[DIY]

Filter is a wet/dry sump system.

In the sump I have main return pump back to tank, and a second small pump that pushes water through a co2 reactor followed by the UV, all external to sump. UV light is fully sealed and there's about 1/2 to 1 meter of eheim hose for water to get through before returning to sump. Not much chance of UV having any impact on the bioballs etc.

EDIT** I just remembered and checked, I have recently replaced the eheim hose with length of clear pvc hose, that hose does run past one small section of bio balls in filter... surely not!! UV light would have to pass through pvc hose, and 6mm of glass to shine on bio balls, even then it wouldn't be able to directly shine on all bio balls only a section !! **

I have a few half baked theories so far. :scratch

1) I totally killed my good nitriying bacteria by the purigen not being properly dechlorinated after bleaching, long shot but it only takes an oversight on my behalf. Nitrifying bacteria is still re-attaching itself to gravel, glass, bio-balls etc but majority is still waterbound and I've just knocked that about by turning on UV too early

2) Something else is in the water, bacteria, parasistes, I don't know what and I'm actally creating a massive bio-load spike by killing whatever that is off when I turn on UV? sounds like a long shot doesn't it :?

3) total coincidence two times running about UV, I happened to do another course of Prazi medicated food on Friday...

[DIY]

Ammonia has reduced greatly after turning of the UV last night :roll:

[bartek]

I have a few questions for you:

1. How big is your tank
2. How big is your sump and what filter media are you using.
3. How long has the tank been running?
4. Did you clean the hose you bought form bunnings before using it?
5. Are you addign any bioculture to the water to help the tank cycle?
6. What is in the tank? substrate etc
7. Where is the water that you are putting in the tank coming from?

I have a 4ft tank with ADA substrate which toll close to a month the cycle.

[DIY]

I have a few questions for you:

1. How big is your tank
2. How big is your sump and what filter media are you using.
3. How long has the tank been running?
4. Did you clean the hose you bought form bunnings before using it?
5. Are you addign any bioculture to the water to help the tank cycle?
6. What is in the tank? substrate etc
7. Where is the water that you are putting in the tank coming from?

I have a 4ft tank with ADA substrate which toll close to a month the cycle.

Hi Bartek - answers to your questions

1. 6x2x2 (slightly under) approx 650 litres
2. 50 litres, 15 litres of bio balls, filter wool/wadding as prefilter
3. Tank has been running since August 2005, almost 3 years...
4. It wasn't new, I actually had used it in another tank before this one, I gave it a clean before putting it on this tank
5. Nope - never needed to, tank has been running since 2005
6. Gravel with laterite and undergravel heating cables for substrate, moderately planted display tank some cardinal tetra's and rummy nose tetra's that have been there since August 2005. Plus my discus of course.
7. Water comes from water aging drum, water is aged with an airstone and heater for minimum 24 hours before use, but usually aged for 3 or 4 days. Prime is added to drum as a safety precaution (chlorine level is very low in my area and will easily gas off using heat and airstone in 24 hour period)

I have used UV light in past with no issues as well... got me stumped. I'm going to wait a bit longer this time and then when I turn on UV again I will be monitoring very, very closely

[bartek]

Well it does seem strange indeed if your tank is so extablished

Has anything changed in the sump to cause a die off of the bacteria for some reason. Have you cleaned the sump reasontly?

I wouldn't think that the UV is the problem but I guess you can try covering the hose. It wouldn't be a big job in anycase.

I runa UV light with no problem what so ever on my 4ft.

Another thought is with regards to purigen. My understanding that once exhausted it may started to leech the amonnia pack into the water. By changing it you may have caused this to happen by distubing the bags. I myself try not to use it for long periods of time for this reason. Its only a quick fix for a week or so if something goes wrong. The same goes for activated carbon.

[DIY]

Another thought is with regards to purigen. My understanding that once exhausted it may started to leech the amonnia pack into the water. By changing it you may have caused this to happen by distubing the bags.

Interesting thought... I've been running purigen for about a year now, normally change the bags about every 4 - 5 weeks and this time it was probably closer to 6 o 7 weeks, a bit longer than normal. It certainly seems the likely culprit of the original ammonia spike was changing the purigen - either been in too long like you say or the re-charged bags I put in were not properly de-chlorinated...

Still doesn't explain why 2 weeks later turning on UV coincides with another ammonia spike, and turning off UV coincides with ammonia levels dropping again... :scratch

[bartek]

Yeah I guess it doesn't explain it.

I wouldn't have purigen in the filter all the time. What is your reason to do so? What do you do if you medicate the tank?

Im not sure but does purigen absorb any nutrients which you may add to the water such as trace minierals etc.

[DIY]

I wouldn't have purigen in the filter all the time

Fair enough - I can understand this, it actually fits with my own conservative view. I was reluctant to try purigen initially but once I saw the results I was sold.


What is your reason to do so?

Improvement in water clarity for a display tank.. basically it's more of a "wow" factor, it looks like the fish are floating on air! No obvious side affects and finally - after reading seachem's literature it is meant to remove dissolved organics which is a good thing.


What do you do if you medicate the tank?

I don't like medicating, IMO fresh clean water assists the fish by allowing the immune system to do it's job, plus medicating a 650+ litre tank is not really wise anyway. If I do medicate I will either use a short bath or put the affected fish in a hopsital tank. Prophylactic med's like Worming is best done in food anyway so purigen is not a consideration.


Im not sure but does purigen absorb any nutrients which you may add to the water such as trace minierals etc.

Well discussed on planted tank forums, and purigen's own literature confirms it removes dissolved organics and has NO effect on trace elements or macro ferts.

[bartek]

Yeah well there you go.

I was more just thinking aloud.

I use a hospital tank as well and I only have a 200L 4ft as your right its just too expensive otherwise.

Don't get me wrong as I have used purigen before and agree that its a great product. I guess it down to individual preference in the end.

[DIY]

Nothing wrong with thinking out loud :lol:

I've removed the purigen since the last ammonia spike anyway to be sure, thanks for the input :thumb

[DIY]

Well, I turned the UV on a couple of days ago, didn't change any hoses and no problem this time so I'm still a bit confused.

I haven't put the purigen back in, maybe the purigen's gone bad or something :ug

[ILLUSN]

you can only regenerate it so many times, once the blech smell stays with it its too far gone and needs to be replaced.

[fishgeek]

water borne algae being killed by uv and as they then breakdown they release ammonia into water column?

combined with your suggestions of damage to biobacter by overcleaning/changing out substrate?

just throwing idea about

andrew

[bartek]

Seems that the purigen may have had something to do with it.

Good thing is that your problem has stopped so at least or all fish will be happy.