QT bacterial bloom and spontaneous ammonia with RO water?

[Mamashack]

I'm in the process of setting up a quarantine tank for some new shrimp I'm getting this week. I'm using the 12L to quarantine the new ones when they arrive in a couple of days. My plan was to use a mature spare filter that has been running in the 60L platy tank for months now. Also going to run it bare-bottomed as it will only be is use for 1-2 weeks at most (hopefully). Planning to put in some leaf litter from the main shrimp tank and a java fern as hiding places and biofilm source for food. also got some Bacter AE arriving tomorrow all being well.

 

I set everything up yesterday altho I didn't put the filter in at that point because I didn't want the bacteria to die back. I used RO water remineralized with Salty Shrimp GH/KH+ and got the following results:

GH 9, 

TDS 250

pH 7.8

temp 22C

 

This morning I got up to a mildly cloudy tank - bacterial bloom sprang to mind as did the thought where did the bacteria come from with RO water? The tank however was not sterile so I guess they came from there.

I decided to check the usual parameters and found the ammonia was 0.5 ppm which shocked me somewhat. 

I know that these are heterotrophic bacteria - are they the source of the ammonia as they die back or reproduce?

My kneejerk reaction was to change all the water, but I managed to resist that and have since put the intended filter in there as it will have an ammonia source to keep it alive and working.

 

Any thoughts on these facts? Could/should I be doing anything differently? I would be grateful for any suggestions.

[mayphly]

I think the cloudiness is just from the sponge. Your filter should clear things up. Give it 24 hours and see. You want the beneficial bacteria to grow in your filter media anyways.

[Mamashack]

Thanks Mayphly - I didn't actually put the filter in until after I spotted the bacterial bloom and got the positive ammonia test so I don't think it was the sponge as it wasn't even in there.

However I will give it til tomorrow morning and if nothing's changed by them I'll add some Tetra Safe Start. 

Does anyone know if these heterotrophic bacteria that caused the bloom can harm the beneficial bacteria? 

[Shrimpo]

The bacteria came from your RO water, I don't think there will be a problem just keep the filter running.

[Mamashack]

Thanks, Shrimpo.

I tested again last night and, altho it was less cloudy, the ammonia was still 0.5 ppm and nitrate less than 1 ppm, but not 0, so I added 30 ml Tetra Safe Start. Got up to a crystal clear tank this morning - ammonia 0.25, nitrite 0, nitrate 2.5 - so things are moving and have added a further 20 ml Safe Start. I'll test again tonight when I get in from work.

The TDS has gone up from 250 to 279 which I'm assuming is from whatever medium the bacteria are carried in. There is no fan on this tank as I want the temp to be good for the bacteria so there shouldn't have been that much evaporation.

Found a poor little assassins snail in the tank this morning, must have hitch-hiked on the anubias from the 60L tank. I'd gently pulled off all the gravel from the roots and never saw it. Put it back in the 60L today and it soon disappeared so hopefully no harm done!

[Pika]

Glad things seem to be back on track for you! I always read these with interest so I can store up knowledge for if this kind of weird/scary thing happens to me in the future!

[Mamashack]

Thanks Pika! That's the beauty of these forums - sharing problems and hoping someone can help and/or preventing someone else from making the same mistakes.

Have retested this evening and the ammonia was 0 and the nitrates 5 so that's a big success as far as I'm concerned.

Looking forward to getting the new shrimp tomorrow!