What are the most important tests for chemistry?

I know several elements are important to keep under control such ammonia, nitrates, nitrites, etc etc. However due to the fact that I have a limited budget and want to get a couple of needed kits now so I know longer have to get the water tested at the LPS, what is the order you would say in importance or they ones you would have to keep the closest eye on. Basically what Im asking is. If you had the money to invest in only 3 tests, what would they be?

Would it be
1.Phosphates
2.Nitrates
3.PH ?

MY tank 46 g. no skimmer. 3 stage media filter, Live rock and sand, very lightly stocked, up for three months, R/O water used. thanks so much.

 

those 3 listed are the ones you want IMO. im assuming you have no corals? if on a budget, and since your tank is new , you can get a cheapie ammonia alert.

 

Most master kits will include all the basic tests - PH, Ammonia, Nitrite, Nitrate, and sometimes Alk/DKH
need to add Calcium, Magnesium, and Alk if it wasnt in the master kit.
optional tests will be phosphate, copper, silicate

 

Those three should get you by fine. No need for more until you start getting corals. I haven't checked my ammonia since my tank cycled, its not needed unless there is a problem.

 

Something like this...

Aquarium Water Testing: Aquarium Pharmaceuticals Saltwater Master Liquid Test Kit

Shipping is 9 bucks regardless of what you buy. If that's all you need though, might be able to find somewhere else(maybe even LFS) cheaper...

 

phosphate test are not optional IMO. absolute must

 

The problem with the master kit is your paying for ammonia and nitrite which are not needed unless you cycling your tank. I still have my original bottles from when I started my tank a year ago.

 

I can understand why some would say that, my own experience over the last 9 months do not indicate a need to test them on a regular basis. They mostly give you a false negative when you have an algae problem because the algae keeps the reading artificially low - the existence of the algae itself is a better indicator.
and i have only felt the need to use my kit twice just to check, I figure the kit will expire long before I get any real use from it.
A ball of chateo and a half dozen mangroves will keep the levels in check as long as your using RO/DI and not phosphate laden tap water.

 

APi reef master test kit, $25 bucks shipped petmountain with 10% discount. "TEN"

calcium,nitrate,dKH,phospate

 

just like to add

I purchased the Salifert PO4 test kit
and like Telgar have barely used it

my opinion is that many people new to the hobby do things in this manner

1 -notice an algae issue
2 -puchase a PO4 test kit
3 - realise they have PO4 problem
4- start using GFO or other PO4 removing compound

well I know thats the way I did it many years ago

this time round
I accepted PO4 was a given
and started running GFO within 3 months of setting up tank
change it every other month
and have tested and recorded 0 x PO4 on maybe 6 occassions in 2 years

for me
Calc, ALK or DKH , Magnesium, Nitrate are the test kits I get most use from
ammonia and Nitrite - I have on hand in case something does not look right

Steve