you can buy your own test kits they are very simple to use. And depends how big the pleco is and if he is fed the right stuff. go to aquabid.com and but some pleco chews. and to clean the tank... buy a marlineland http://www.petsmart.com/product/index.jsp?productId=2752362 sure it may be a little pricy but hey thats what i use and it works!