Bacteria Bloom - Question (Update)

[Essjay]

Topping up with distilled is fine between water changes, but water changes should be done with whatever the tank was filled with at the start.
As you are doing a fish-in cycle, you do need to do a lot of water changes. Fish-in cycles involve testing every day and doing a water change whenever ammonia or nitrite read above zero. Using distilled for water changes lowers things like hardness which is not good for the fish, which us why they should be done with the same water as when the tank was first filled to keep the levels constant.

 

[Jaybird]

Thanks Essjay,

Thanks for the advice, I understand what you are saying and I believe I have my answer now.

My situation is that I have a new 10g tank (that did run with no fish for about 4 weeks prior to adding fish), 4 fish presently inside, that is now experiencing a BB. I didn't not want to add or replace any water during the bloom with tap water if I didn't have to. After the span of several days or more waiting for the bloom to subside my tank water level has started to deplete. Not wanting to add more tap water in fear of "feeding" the bloom, I was wondering what type of water to top up my tank with so as to not make the bloom worse (which you answered with suggesting pure water).

Once the bloom has cleared up, I will resume with my regular water changes as you suggested.

 

[Byron]

Tap water isn't "nutrient rich", not sure what he meant by that...it contains trace minerals, yes, but nothing that would support the BB colony growing faster.

This is not actually true. A bacterial bloom in a new tank is due to the high level of dissolved organics in the tap water. Dechlorinating the tap water allows the waste-eating bacteria to multiply which they do rapidly because of the high organic level in tap water. These bacteria can reproduce within 15 to 60 minutes. You can read more in my article here:

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[Essjay]

If you just let the tank run for 4 weeks, it was not cycled when you put the fish in. If there are lots of live plants, that was a plant cycle, but no plants or no added ammonia means you are doing a fish in cycle.

Test the water for ammonia and nitrite every day. If there is any reading above zero the fish will be harmed so a water change is needed even if it feeds the bloom bacteria. In this scenario the choice is clear water and sick fish, or healthy fish and cloudy water. The cloudiness does not harm fish but ammonia and nitrite do.

 

[Byron]

Thanks Essjay,

Thanks for the advice, I understand what you are saying and I believe I have my answer now.

My situation is that I have a new 10g tank (that did run with no fish for about 4 weeks prior to adding fish), 4 fish presently inside, that is now experiencing a BB. I didn't not want to add or replace any water during the bloom with tap water if I didn't have to. After the span of several days or more waiting for the bloom to subside my tank water level has started to deplete. Not wanting to add more tap water in fear of "feeding" the bloom, I was wondering what type of water to top up my tank with so as to not make the bloom worse (which you answered with suggesting pure water).

Once the bloom has cleared up, I will resume with my regular water changes as you suggested.

There is a danger here that should be pointed out. I don't know how much water is evaporating, but adding water with different parameters from the tank water can slowly change the tank water parameters. When you do the next normal water change, it may be a considerable difference that can be harmful to fish, depending upon the initial tap water parameters and the tank water parameters.

Personally I would not ever suggest "topping up" for reasons already noted by me and @Essjay . A water change with same-parameter water is better for the long-term stability of the biological system. I recognize the bacterial bloom issue, but this is one of those cases where taking one road to avoid "x" may be worse for the fish/system than taking another road.

 

[Jaybird]

Just an update....

I've been testing my water and all seems ok for now, I have no dangerous levels of anything.
I've been adding some beneficial bacteria to my water and letting the filter do it's job thus far and also doing small water changes every week.

I'm happy to say that my water has begun to clear up albeit it's a slow process... I've seen a few advice columns say it should clear up within a 'few days' but my bloom has been going on several weeks already and is now only showing improvement after adding some beneficial bacteria over the span of a few days straight.

My fish seem ok too (2 danios - 2 Cory's) and show no signs of stress from what I can tell so I'm happy for their health at this point.

I'm hoping the beneficial bacteria works exponentially and accelerates the clearing process. We'll see over the next few days.

Thanks everyone again for the solid advice!

 

[DoubleDutch]

What benificial bacteria exactly did you add?

 

[Essjay]

The beneficial bacteria we add to cycle a tank won't clear a bacterial bloom. The bloom bacteria die when they have eaten all their food. Their food is carbon based; the filter bacteria's food is nitrogen based.

 

[Jaybird]

I added a little Nutrafin Cycle.

Maybe it was just coincidence then but a day or two after adding some my water began to clear. I figured there wasn't much harm in trying.
Either way I'm just happy it's starting to clear slowly.
I'm continuing to do partial water changes and gravel cleaning.. maybe that's all it needed. Testing water regularly too.

Regards.