I recently bought a 75 gal tank for Tanganyikans, but I haven't gotten then yet so the plants will have a head start. Until then I've put two dozen guppies in the tank to keep nitrate levels fairly high to stimulate plant growth. The problem is the guppies havent been doing so well. Within the first few days I lost a few to the stress and a mild outbreak of ich caused by the stress. The ich cleared in 3 days or so and everything seemed fine. Unfortunatley they kept it up and in the first week and a half 2/3 of them had died and as of a week ago there was only 4. Its not so bad since most were pregnant and I ended up with 40+ fry. A few days ago one more died and the half grown fry are dying every once in a while though I still have about as many fish as I did when I bought them. Thats probabally too mutch info but what the hell. Now I'm wondering whats the problem? I'd like to solve it before I sink money into the cichlids.
I know its not ammonia poisoning because ammonia levels are at zero and despite the original plan nitrates are at zero also. pH is alkaline; I dont know the exact numbers but its up there. dH is fairly high also, but like pH I dont have an exact figure.
From the time it took the guppies to die, Im guessing some kind of metals poisoning, but I have no idea. If anyone has an idea of whats going on I'd appreciate the help.

that little bit of biomass wouldnt help raise nitrates, a 75 wouldnt even notice a couple dozen guppies being added. for those water parameters you could try getting some big mollies, but im guessing you bought feeder guppies for their low cost and the mollies would be more expensive. are you sure the cichlids you are wanting wont just destroy the plants? many african cichlids are highly herbivorous, that is why it is very uncommon to see a planted african cichlid tank. if you got feeders most likely they were already sick and stressed before you got them. in such a large tank it would also be very hard to feed all the fry without polluting the tank. which species of cichlids are you wanting exactly?

Do you have other tanks up right now that are okay? Have you kept guppies okay in other tanks? If so, this may have been a bad batch of guppies. The ich and stress may have finished them off quickly. If they were feeder guppies, they would be in poor health at most stores when you got them. List everything in the tank for us to see if something sticks out as problematic (as far as metals poisoning or other things). Also, list any water additives that you used. Do the survivors show any symptoms of ick or other things? Do you have carbon in the filter? It would help remove any organic or inorganic (such as heavy metal) toxins.

If the tank is heavily planted and doing okay as far as the plants go, the fry should find natural foods to eat in addition to anything added. Usually African cichlids are kept in high pH and very hard water tanks with rocks and no plants (few can take such hard water and high pH).

As for the cichlid species, I'm sticking to carnivores. The only problem would be rooting fish damaging the root structure of the plants. The ones I'm looking at are mostly Neolamprologus species and Julis along with a school of leptosomas whatever else I get depends on what's available. I know the julis might be a problem, but I'm going only stock a few and the plants are either inedible or hardy.

I do have a carbon filter. There are no additives to the tank water. This is my first tank since moving last year so its the only one up now. The guppies show no simptoms and look healthy except when one dies suddenly every once in a while. I can't get tests on alkalinity and water hardness until I go into town in the next few days to get kits. I've only had amazonian tanks so I haven't had to worry about either before. I'm looking for the well water comp report which should have the chemical and metals levels in it. However if I remember correctly everything things are low except for salts and pH which is why I decided on a Tanganyikan tank.

This is kinda unrelated but I have a snail infestation and Im curious what species they are. The only eat dead matter (dead fish and leaves) and algae and havent touched the plants. The biggest ones so far are about 1/4 in long but they're only two months old.
Also i havent been able to find a good inch per galon formula that takes filtration into consideration. The tank has about 60 gallons of water space and the tank is recirculated about every 10 min. If i could get some numbers that would be great.

What do the snails look like? My snail species page is at http://www.fishpondinfo.com/snail2.htm

The rules for tank stocking aren't set in stone. There are too many variables. It's not only the mass of fish (not length) per gallon that matters but indeed the filtration setup and how often and how much water is changed and many other things.

Hey. Sorry i dissapeared like that. I went on vacation before i could test the water. Anyways, the water seems to be fine since all the surviving guppies are fully and near fully grown and healthy.
I have noticed that the colors are more vibrant than their parents and am wondering if the relative dullness of the original guppies was because of high stress and/or poor health.