20 gal. guppy tank issues.

[ZSchoonover]

Hey so back in October I decided to get into planted tanks. I've had previous experience with fish tanks but have never gone the planted route. I've also been trying to get into guppy breeding as well. After planting the tank and stocking it with my guppies I found that a few months in my fish started dying off one by one. After doing some research I came to the conclusion that it was due to finrot and possibly ich. I ended up treating the tank for 10 days with both Microbe-Lift ML/H and ML/A. This cured the problem. After restocking the tank, a few months later my fish started dying off again. Same issues as before. This confused me because at the time I had been doing a 50% water change every week and my levels were all fine.

Well yesterday morning I woke and all 3 adult guppies had died but my four adolescent guppies were fine. This was on Tuesday morning and my last water change was Friday before. I tested the water parameters and came up with 7.2pH 0Nitrate 0Nitrite and 0Ammonia 80*F. This is about average for my tank as I test the levels once a week. The only additions to the tank were 5 ghost shrimp on Sunday to clean up some string algea on my plants.

Can anyone help me with this? I am a little frustrated because I thought I had been doing everything right but my fish keep dying. Thanks in advance.

Setup...
Tank: 20 gal
Filter: AquaClear (50) Carbon removed
Light: 15W Aqua-Glo (18,000K?)
Sponge filter (for oxygen)
100W heater set at 80*
Gravel: Eco Complete (Planted Aquarium Substrate)
Plants: Java Fern, Water Sprite, Wysteria, Amazon Sword, Jungle Val.
Fish 5Ghost Shrimp 1Pleco 4Juvenile Guppies (3Adult Guppies (KIA)
Buffer/Conditioner: Microbe-Lift XTreme

 

[Chad2000k]

I don't have a whole lot of experience in this but shouldn't there be some sort of Nitrate in the tank? I have 3 male guppies in a 5.5 gal tank, my temp is set to about 75°F or 76°F. A good friend of mine told me not to go above 78°F with the guppies, for some reason it enters a more likely diseased realm with the water so warm. Found a link that he uses "An ideal temperature for adult guppies is 72° to 76° F. Fry are often raised in warmer water for the first 2 or 3 months (78° - 80° F). However, guppies can survive temperatures as low as 60°F and as high as 90°F. The higher the temperature in which a guppy lives, the shorter it's life span will be." - Guppy Facts Hopefully this helps a little bit maybe?

 

[ZSchoonover]

Ok so I did just drop the temperature down to about 77*. Hopefully this will solve the issues with diseases. As for the nitrates. I'm still doing about a 40% water change once a week. I've heard mixed opinions about large water changes but in my own experience with my other tanks this has been very beneficial.
I have a 5gal fluval spec with 5 rams in it and do the same procedure. Most of the time the numbers are the same as my 20gal with the exception of the pH.

 

[Chad2000k]

I'm doing about a 36% water change to my tank every other day to get it though this cycle stage. This is the only way beneficial to keep the nitrates and ammonia down without going into toxic levels. Once the nitrates level off, you should be okay to doing half that about 20% or so water changes a week just to save water...

 

[creic38]

Not having nitrates is not a bad thing, unless you are keeping live plants. Even then, if you had small amounts of nitrates you would probably get zero readings because your plants would be using them up. The only other things that nitrates tell you are a) your cycle is working and b) if they are high, then you are not changing out the water enough. As for your guppies, not sure why that is happening. Do you have the correct ratio of male to female? If you have more males, they are probably harassing the hell out of the female and each other.