Jo and Gra said:
so liquid test kits........
how often should i look to be testing?
and how long wil one "kit" last?
During cycling, you should test daily. If you are are doing a fishless cycle as the title says, you really only need to test for ammonia until the ammonia starts to drop. Once it drops to zero, you will continue to add ammonia daily to raise the level back up to 1 to 2 ppm. Start testing nitrite also. You should test them both daily until the nitrite spike ends and it drops to zero. At that point, do a large 75 - 90 percent water change to get rid of your nitrates.and then test your nitrates. You can also test nitrates occasionally during the nitrite spike just to see how high their getting (they will go off the chart as will nitrite). They should probably be 20 ppm or less after tha water change. After you add your fish, I would test daily for ammonia, nitrite and pH for at least a couple weeks just to make sure nothing strange is happening. Once you are satisfied that the tank is properly cycled, you can cut back to testing everything once a week. You should definitely start daily tests again any time you add new fish or make any change in what you are doing with the tank.
One other thing is that you should test your tap water to see if you will be introducing anything during water chages. Some water (especially well water) has nitrates, ammonia and nitrite already present. Also, anytime you buy fish and bring them home, test the pH of the water in the bag from the LFS before you start to acclimate them. There can be a sizable difference sometimes between their pH and yours. If that is the case, you will have to take special steps to insure that you don't send your new fish into pH shock.
problems with this method.
Lastly, the kits will last you anywhere from a couple months to a year or more. I got my first tank at Christmas last year. I started with the same API Master Kit that everyone else has recommended (I will also say I think it is the best). I have recently had to buy a new ammonia, nitrite and pH kit. Of course, I now have 5 tanks that I have been testing. Once you are more familiar with what your water is doing, testing for nitrate may not be an issue. Mine never goes above about 5 to 10 ppm so I rarely test it any more. Also, the master kit has a pH and High pH kit. Unless your pH is right at the 7.4 range, you will almost never have the need to use one or the other. If your pH generally runs at 7.0 or less, all you will need is the regular bottles. If it runs over 7.6, you only need the high pH tests.
This is just my experiences. I'm sure others do things differently but I haven't had any