Hi

I know that u can use baking soda to raise ta but i already have a tub of ta increase will this raise ph as well?
Also am i correct that ph increaser will raise ta and that u need to use borax cause im in the UK and we don't have borax and i don't know what the equivalent is.

Baking soda and TA Increaser are exactly the same stuff, sodium bicarbonate, give or take how pure and how finely ground up it is. Baking soda is not very useful for raising PH in a swimming pool. While baking soda does raise PH, it doesn't normally do so by enough to be useful. If you need to raise the PH your best choice is borax. If you can't get borax, soda ash, often sold under other names like PH Increaser, is your second best choice. Soda ash will raise the TA more than borax does (both raise the TA some). In most situations that isn't a problem. The only time it makes a big difference is when you are keeping TA very low to compensate for CH levels being very high.

Borax is sodium tetraborate decahydrate. If you are purchasing large quantities you can find it fairly easily from chemical supply dealers, but finding smaller quantities can sometimes be problematic in places where borax is not available. Pool stores often carry sodium tetra borate pentahydrate under various brand names (Optimizer, Supreme, Endure), which is a somewhat more concentrated form of the same thing as borax, but the brand name products tend to be expensive.

You can buy borax in the U.K. from Mistral (similar link here) and other sources listed on a search on Amazon and Google (just look for purity and stay away from the Borax substitute since that is sodium sesquicarbonate). The sources from R & D Laboratories are the same as Mistral since R & D Laboratories Limited is the parent company of Mistral Lab Chemicals.

As noted here, Borax may eventually be banned in the EU (including the U.K.) though that has not yet happened and may not happen. Borax (and boric acid) are dangerous if ingested in larger quantities which is more likely when dealing with borax in concentrated form so if used as a dust that people are regularly exposed to, then that can be a problem. This is not new information and I've written about boron toxicity in the thread "Are Borates Save to Use?". It's used in laundry detergents at lower concentrations of a few percent and similarly in eye washes at 1-2%. In pools, it is used at 50 ppm which is 0.005% (in Boron weight units -- around 0.03% in boric acid weight units). Basically, care should be taken when dosing the concentrated product, but once diluted in pool water it is safe assuming one does not drink copious amounts of pool water on a daily basis.