I will transfer the money on Monday.

Please tell Tuncay only to use the minimum amount of chemicals. The pool will not be used until May.

Thank you in advance

 my attempt

Pazartesi´e parayý yollayacaðým. Lütfen Tuncay´a sadece asgari kimyasal kollanmak söyle. Biz havuz a kadar Mayýs kullanmayaycaðýz.

I have altered it slightly to say I will send the money on Monday. Please tell Tuncay to use the minimum chemicals. We wil not use the pool until May.

Will this be understood? I appreciate it is a little basic

Thanks in advance

Above is the correction of your version. It was understandable but maybe your last sentence was not understandable  because you used "a kadar" before "mayýs", it has to be after.

Pazartesi parayý yollayacaðým. Lütfen Tuncay´a sadece asgari miktarda kimyasal kullanmasýný söyle. Havuz mayýsa kadar kullanýlmayacak. 

(p.s.: the first letter of month names are written in capital only if they are indicating a definite date, i.e. "20 Mayýs´ta geleceðiz"; but if you write only the month,it is not in capital "mayýsta geleceðiz")

 thank you very much dilliduduk. I will try to remember your corrections - thanks for the advice