[irishlep]

Iam having problems keeping ph levels in my 65 gal tank. Also the Alk seems to be off when I test with the dip strips. I use RO water and change 20% once a month, and always keeping the water level up using RO water.
Could someone recommend a good tester for PH and ALK?

[pearl_aqg]

In freshwater most hobbyists end up going with more or less the natural pH of their water, from the tap or filter (RO filters actually lower your pH). It's difficult to make lasting changes to pH, and freshwater fish are capable of adapting to a pretty wide pH range as long as they're allowed to do it slowly.

In saltwater where it's more important to keep pH up, you can raise the pH for the longterm by using crushed coral or aragonite sand as substrates. I would steer clear of short term pH adjusters. There are marine buffering solutions that might help too, Kent and Seachem make a few.

As far as test kits go I always hear that Salifert's are the best, though they can be hard to get due to high demand. Seachem's get great reviews too.

[Samper]

I wouldn't get a crushed coral substrate. It will end up being a NO3 factory and cause you a whole other set of problems. Instead get a CaCO3 sand. Salifert and LaMotte make the best kits but I use a Milwaukee digital probe to test my pH. The next time I buy a probe and controller it will possibly be a pinpoint for more accuracy. The Milwaukee only reads to one decimal place and the pinpoints show two. Your best bet after you make sure your pH is actually where you think it is is to go to your Grocery store or Wal Mart and get Food Grade pickling lime. I can always find Wages in the canning section. It comes in a white plastic jar with a green lid. Make sure it is pure food grade...I've seen some that had some other ingredients in it for flavors and such. After you get that go to your hardware store and pick up a threaded 1/4" ball valve some plastic weld and a rubbermaid with a good tight fitting lid. Drill you a hole just large enough to screw that ball valve into about 2" off the bottom. Screw your valve in it and then seal it with the plastic weld inside and out. Attach some 1/4" water line just like what runs on your RO/DI to the outside of it and you have a home made doser. When it dries simply put a cup or so of the pickling lime in it and fill it with RO water. Mix it with a spatula or something and let it settle for a few hours before starting the drip. Drip it at night or 24/7 depending on your needs but drip it slowly. I like to drip mine into the intake of my skimmer.