When to vacuum?

Stacie H.
  • #1
HI All,

I always find helpful advice here, so here I am again.

I have had a 36 gallon tank since February. I have 2 peppered corys, 4 harlequin rasbora, 5 black-skirt tetras, 4 von rio flame tetras, and 3 rosy tetras. Well within the limits, I feel.

It took a long time to cycle, due to some errors on my part. However, for some time now, my ammonia and nitrites have been at 0, and my nitrates WELL under 40.

My biggest problem now is that my tank, while much, MUCH clearer than before, almost always has a bit of haziness. I think it's mostly algae, because I see a light film on the inside of the glass.

I'm nervous about vacuuming, because in the beginning I vacuumed too much, and sent the tank into another cycle. I have been scraping the sides and letting filter remove the algae, which has helped. The tank is a pie-shaped tank and sits in the corner of our living room. Yes, it is next to a window, but it's a south-facing window, and the blinds are always closed. The room gets a ton of natural light (big windows), but not direct sunlight.

I've also had a couple of deaths lately, one of my rasbora and one of my von rio flames. The rasbora died the day after I brought them home, and I bought them at a LFS that I had never used before, so I'm blaming the LFS. The von rio died a couple of days later, so I don't know if the rasboras were/are sick. Everyone else seems fine so far...no ick, etc. I checked the water each time, and it was fine.

My biggest frustration is how to get rid of the cloudiness/haziness??? I have been using Algae Fix. I broke a personal rule today and used some of my Accu Clear. I only did this because a few of the fish have been hanging out in the back of the tank, and with the recent deaths, I want to keep an eye on them.

Any tips? What type of routine should I get into as far as water changes/vacuuming?

  • #2
If you have algae and no algae-eating fish, you can get one algae eater such as the Bristlenose or the Siamese Flying Fox (Crossocheilus Siamensis - this is the true Siamese Flying Fox, so don't get it confused with another fish).

If your nitrate is close to 40 ppm, you should perform larger and/or more frequent water changes. While nitrate can go up to 40ppm and still be safe, I'd personally NOT let it rise that much. I wouldn't keep nitrate above 20 - that would be the limit for me. The haziness may be the result of too much nitrate.

Now, when you perform a water change (with a gravel vac) and you clean the filter sponge at the same time, you may be removing too much bacteria and therefore causing a mini-cycle. It's best to perform a water change with a gravel vac, say, today, and clean the filter a few days later. When you clean the filter, ALWAYS do it in your tank water (take some tank water in a bucket), because if you do it in your tap water, all the bacteria get killed by chlorine in the water, and you have to cycle the tank again.

Vacuuming a tank's bottom should not cause any mini-cycles. You should always vacuum the gravel with each water change in order to remove the accumulated and rotting fish food as well as fish wastes from there. If you let them decompose there, they'll increase your nitrate greatly and decrease your pH. Remember to perform the water changes REGULARLY because if you let the tank be unattended for a long time - during which a lot of nitrate has accumulated - and then perform a sudden water change, the fish may experience a great shock suddenly going from high to low nitrate.

If you perform regular water changes (say, 15-30% weekly), you should have no haziness. If you still have it with regular water changes, try activated carbon in your filter - it should clear the water. If you use any commercial products in your water (such as the anti-algae product you use), they may cause cloudiness. Perhaps that's what is causing haziness in your tank. I believe the best way to fight algae is to get a good algae eating fish and NOT by adding chemicals to your water.

  • #3
If you are worried about upsetting the bacteria, you can vacuum one half of the gravel one week and the other half the next week, so you only disturb half at a time. But it definitely needs to be vacuumed. If the gravel is dirty, bad bacteria will begin to grow there, and that will eat away at the barbels of your Cories.
Stacie H.
  • Thread Starter
  • #4
An update:

It's going much better, the tank is all but clear. I lost another rasbora the other night. He'd been acting strange for some time, then all of a sudden he went belly up, right in front of us.

I just tested my levels:

Ammonia 0
Nitrite 0
Nitrate was hard to determine...higher than 0, but less than 5.0
pH 7.6
  • #5
Glad things are going better
  • #6
If there were no signs of any diseases on your fish, maybe it died because of old age (maybe it has a naturally short life span), or it may have been growing in poor conditions when it was still young. When fish are raised in poor conditions, they may live shorter lives. Three of my neon tetras died (not all at the same time, but in few-month intervals) like this too - no symptoms of any disease whatsoever, my water quality was very good, and yet they just died. I was baffled too.
  • #7
I had a terrible time with algae and haziness in a tank. Here's what I did and it worked extremely well. Totally blackout any light coming into the tank by covering it and leaving as such for 3 days. On the third day, remove the covering and do a 50% water change. This worked wonders for a tank I had algae as well as haziness in. I know it can be stressful on fish to leave lights off but it is only for a few days.

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