Freshwater Setup, Silicone Seal Problem, & Fish Selection

Question
I have a 30 gal glass tank which previously housed aquatic turtles. I cleaned the tank with vinegar and noticed that the turtles picked at the silicone near the joint where the back panel of glass meets the bottom. I tested it by putting about 5 gallons of water in the tank and let it sit for a a few days to see if it would leak out all over the floor. I have had no leaks so far. I didn't want 30 gallons of water spilling out while I was at work. Is there any other recommendations for testing or repairing the tank? Should I add more water or do you think it's okay? If I need to repair it, is there a specific type of silicone I need? I know that RTV silicone sold at home improvement stores is toxic until it cures, but is it safe for fishtanks?

My tank came with a pretty new FLUVAL 203 pump (with NEW replacement foam inserts, activated carbon, and pre-filter media (ceramic "noodles"). It also had come with a floating mercury thermometer - is this type of thermometer is better than the stick on the glass color changing type?  The tank also came with a thermaflow automatic aquarium heater 12". I was advised to pick up a new water test kit, so I got a freshwater master testkit which measures pH, High pH, Ammonia, Nitrite, and Nitrate. I also picked up some StressCoat additive. I would like to know if you recommend anything else (I don't want to go out and spend a fortune replacing the filter and other components at this time).

I am considering a freshwater stingray (dwarf variety). I don't know if these are legal in my state (CT), but seeing as how  I saw one at a local fish store, I was thinking that they probably are? I've read quite a bit about them and I know that I will need to eventually move it to a bigger tank when it gets large. The one I am considering is not even 4" (disc size). I would like to have this and possibly a couple of angel and/or discus, which I've heard are good tankmates for a ray. I want to get some sort of algae/waste-eater fish, but I've heard you have to be careful as plecos will sometimes "vacuume" a ray and cause damage. I've heard snails multiply like crazy, so I wanted to avoid snails. Are there any small pleco catfish you can recommend? I know there are many species and many get quite large. Any idea of the rate of how fast they grow (inches over time?) If I can find a small one that won't grow too large, too fast, that might be a good approach.

I know rays need substrate (gravel) that is relatively smooth and I would like recommendations on sand vs gravel, or whether a mixture of both might be a good idea? I'd like to have some live plants in this tank as well. I don't know what types are recommended or what the substrate requirements need to be for live plants?

Considering that the fish I want in my tank are a bit costly and the tank is empty, I would prefer to cycle the tank with some smaller, inexpensive fish, like guppies or tetra, which I can move to a smaller 10 gal tank when I am ready to add the other fish.  I also need recommendations for cycling this tank, when to add the fish, how many to add, and at what intervals to keep them at optimal health during initial tank setup?

Also, when I am ready to add the angels/discus, how many to add at once and how often to wait before adding new fish?  I'd like to stick to the smaller angels/discus, but they need to be large enough so the ray won't eat them. I am thinking of gold marbled or black marbled angelfish. Can you tell me the rate of growth on these types of fish (angels and discus)? I don't want to overstock this tank, but I'd really prefer to start with the smaller (2" or less) so I can keep a few of the same type together for less stress on the fish. Are there salt requirements for any of these fish?

Also, for my other (10 gal) tank, I was curious if guppies and neon tetras can be put together?

Sorry for all the questions. Looking forward to your answers...

Answer
Hi Jay,
I have found the best way to test a tank is to just fill it up and wait a few days and see if there are any leaks. I had a 105 gallon Oceanic tank (this brand always has very thick glass) that had an object fall from a shelf and caused a very large chunk of glass to break right at the seams. This was really irritating and I thought that I was going to have to throw it away. Well, to make a long story short, I read on several websites how to repair it and ended up just deciding to buy aquarium sealant and really apply alot to the area that had the huge chunk cracked.(I applied it all to the inside area) I bought the sealant at the  fish store but most Walmart stores have it in the aquarium area, too. So far the tank hasn't leaked at all for over a year. Not even a drop. I don't know if you want to risk your tank leaking but if you fill it and nothing happens, I would probably just not worry about it. Of course, that's up to you. I'm really living on the wild side by taking the chance of 105 gallons of water being in my living room, but so far everything is fine.

Sounds like your filter will be ok and the thermometer too. Good for you getting a water test kit! I agree about not spending too much on equipment.If all seems to be in good working order then it should be fine. Stress coat is good, I use it all the time.

You are really smart to research about the fish you are planning to buy. Most people don't, so good for you! It does seem that freshwater stingrays are illegal in alot of states but if you are seeing them for sale then maybe it is ok in your location. I don't know if you have looked at this website but it also refers to some other websites that have alot of info on how to care for them and where to buy different types.
http://www.aquariumfish.net/catalog_pages/wild/sting_rays.htm
As for a bottom feeder, I have a bristle nose pleco and he will only get around 5-6" and doesn't seem to bother any other fish. I know some do want to eat the slime on other fish but so far he has really been good. All those bristles on his face look pretty cool too.

I don't know if you can have plants with a ray. You could try some of the larger leaved types and see how they do. They need alot of swimming room and they will also disturb to substrate. Everyone recommends the article that Bob Fenner wrote concerning rays and I thought, that if you haven't read it yet it might answer some of  your questions on the substrate and feeding also.
http://www.wetwebmedia.com/FWSubWebIndex/fwstingrays.htm

You can cycle a tank with small fish very easily. I have used black skirt tetras or zebra danios. I usually only use about 2 or 3 and then I make sure that I do partial water changes during the cycling which takes around 3-6 wks. Remove about 1/3 of the tank water at least twice a week--more if ammonia starts to really get high or nitrites.If ammonia gets too  high immediately do a 50% water changed to bring it down and to make the fish more comfortable and not risk the chance of fish death. Check your filter once a week and if it really looks dirty lightly rinse it in aquarium water not tap. You don't want to kill any bacteria that is trying to establish in your filter media and tap water will do it. Be sure to always  dechlorinate your water and make sure it is the same temperature as your tank water. Alot of people add beneficial bacteria such as Cycle or Bio Spira to help get the bacteria going faster.

When you get ammonia and nitrite at 0 then your tank has cycled. When you decide to add the permanent fish for your tank do it gradually, not all at once. Allow a week or two between additions so the bacteria can adjust to the new bio load with each new addition. Be sure to get a schedule  set up to do water changes frequently. Most water problems can be corrected just by keeping up with water changes and tank maintenance. Don't overstock and don't overfeed,please! It can get really crazy fast if you do either.

I raise angelfish and they will grow fairly fast if their water conditions are good. They like planted tanks so I don't know how they will do if your ray uproots the plants. You might try putting plants in little clay pots so they don't get uprooted as easily. I've seen this done in aquariums that have fish that are really hard on plants.
Discus also have to have really clean water to grow and remain healthy so you will really have to stay  up on the tank maintenance.
With both of these fish you really need to have several so there isn't a chance of one picking on another. Even though both types of fish are not really aggressive, I have had my angels really tear up one of my males.You have to always remember they are still cichlids and cichlids always have there little disputes.Oh, and you shouldn't need any salt in the tank either.

As for your 10 gallon, yes, guppies and neons should get along. If you are planning to use the fish that I suggested for cycling they would get along with them also. Oh, I wouldn't use neons to do the cycling--they are a little more delicate than some of the other fish and might not make through the cycling.

I hope you can get your tank set up and everything works out great.
Best of luck.
I hope this has helped,
Karen