Problems with RO water

I set up a new 10 gallon tank two weeks ago with RO water from our kitchen filter. My kids didn't want to wait for a full nitrogen cycle so we decided to try for a fish-in cycle with two guppies. I treated the water with Stress Coat but nothing else.

We've had the guppies for about 48 hours now and they are not happy: lethargic, at the top of the tank, not eating.

I took a water sample to the pet store for testing. Ammonia and nitrates were zero. PH was 7. He said overall it looked really good but was different from their water because they use tap, not RO, and the tap water here is really hard. The guy had me buy aquarium salt, which I have now applied. The salt didn't seem to make a difference but it didn't kill the guppies either.

I am waiting for a variety of water test kits to arrive via Amazon but I did have some water hardness strips that we use with our water softener. The hardness in the tank measured 50 ppm after I added the aquarium salt. Our tap water is about 300 ppm.

What should I be doing here? I'm feeling like the RO water is the problem, but I'd like to keep using it because who knows what's in our tap. My thanks in advance for any insights on this situation.

 

Are you remineralizing the RO water at all? I've never kept Guppies, and could be wildly wrong so please let someone else confirm or correct me, but I'm under the impression that they like harder water. Remineralizing with Equilibrium (or something like it) along with some sort of KH buffer would put back a bunch of the minerals that they need.

 

If you didn't remineralize and didn't acclimate then it could be osmotic/salinity shock.

 

I thought the aquarium salt remineralized it. Is this not correct?

 

Guppies can live in full marine set ups . Salt won't hurt them but is not needed at all .
Neither is RO water for guppies .As mentioned hard water is what they like .
IMO you would be better suited using tap then remineralizing RO ..
Buffers have limitations ..
What do you plan on stocking after the tank is cycled ?
I would do a 50% water change adding back your tap to start the hardness increase gradually ..

 

I thought the aquarium salt remineralized it. Is this not correct?

Water hardness is mostly gH (calcium, magnesium) and kH (carbonate and bicarbonate). Aquarium salt has none of those but will increase the salinity of water with sodium and chloride which are beneficial in many ways.

If the salt was added after the fish then the damage was already done. If this is the case I would remineralize slowly so as to not shock the fish again. Fish survival after any injury is almost always higher in harder water.

 

Yes, the salt was added after the fish.

So how about changing 25% of the water today and 25% tomorrow, adding tap water? If I treat the tap water with Stress Coat is that enough? Should I add the salt to the new water or skip it?

 

Use a de chlorinator if you have it .Not sure stress coat dechlorinates ?
25% is a good start and following up tomorrow will help I think .
What do you plan on stocking ? Are guppies the end game for this tank or just cycling fish ?

 

The longterm plan is still TBD. I'm looking for something tough that will please the kids - guppies, neon tetras, maybe a pleco or some snails.

 

Yes, the salt was added after the fish.

So how about changing 25% of the water today and 25% tomorrow, adding tap water? If I treat the tap water with Stress Coat is that enough? Should I add the salt to the new water or skip it?

I would try to keep the salinity of the water the same.

 

So I replaced 25% of the water but I did it with the water from the kitchen tap, which comes out of our softener. While somewhat harder than the RO water, it's still pretty soft. I then went ahead with another 25% water change using unsoftened water from the outdoor spigot. The guppies were looking at me like, "You really have no idea what you are doing, do you?"

Bless them these little fish are still alive, but I am increasingly worried about one of them. I'll continue to change out 25% of the water each day until they look better.

 

I've done three 25% water changes. The hardness is now up at about 10 grains, which is very hard and not too far off of the straight tap water. I think the hardness issue is behind us.

I discovered this morning that when the kids have been going to turn off the light at night, they were in fact turning off the power strip, meaning that they have been turning off the filter at night. So there has been zero water circulation at night. I'm thinking this may be contributing to the unhappiness of the guppies.

The guppies are looking increasingly ragged. One now has a red spot on his back and is not eating at all. The other looks better and does eat. The Stress Zyme arrived and I applied it. I can't think of anything else to do. Hopefully with the filter on 24/7, they will begin to feel better.

 

Red spot might be a sign of a bacterial infection.

 

Red spot might be a sign of a bacterial infection.

Thanks. I'll look into addressing that.