CTLR VECTORING 2 LTT ACFT FOR VISUAL APCH TO HOU HAD LESS THAN STANDARD SEPARATION; CTLR DISTRACTED BY OTHER TRAFFIC.

Narrative

LTT X WAS ON A RIGHT DOWNWIND FOR RWY 12R AT HOBBY ARPT. LTT Y WAS ON A LEFT DOWNWIND FOR RWY 12R AT HOBBY ARPT. LTT X WAS TURNED TO A HDG OF 100 DEGS AND INSTRUCTED TO JOIN THE RWY 12R LOC AND DSNDED TO 2000' FROM 6000' MSL. LTT Y WAS TURN TO A HDG OF 200 DEGS AND DSNDED TO 2000' MSL FROM 6000' MSL MY ATTN WAS DISTRACTED AT THIS TIME WITH AN ACR MLG THAT HAD TO BE BROKEN OUT OFF OF FINAL. WHEN I REALIZED IT; THE SEP HAD BEEN LOST AND I ISSUED TFC. HOWEVER; NEITHER ACFT COULD SEE THE OTHER ONE; EVEN THOUGH THE VIS WAS 20 MI. THERE WAS NEVER A DANGER OF THE ACFT HITTING EACH OTHER. HOWEVER; I DID ISSUE A TURN OF 270 DEGS TO LTT Y. LTT X FLEW APPROX 5 MI ON DOWNWIND BEFORE STARTING HIS TURN AND LTT Y STARTED HIS TURN IMMEDIATELY AFTER RECEIVING INSTRUCTIONS FOR THE TURN. HAD LTT X STARTED A TURN WHEN INSTRUCTED THE LOSS OF SEP WOULD NOT HAVE OCCURRED. CALLBACK CONVERSATIONS WITH RPTR REVEALED THE FOLLOWING: RPTR GAVE TYPE ACFT INVOLVED AND PROX OF TFC. RPTR WAS WORKING 3 POSITIONS COMBINED AT THE TIME OF THE INCIDENT; BUT DID STATE THAT TFC WAS LIGHT. ACR MLG BROKE OFF HIS APCH APPARENTLY FOR TFC THAT HOU TWR HAD. RPTR GAVE EXPERIENCE LEVEL. TFC ADVISORIES WERE GIVEN AND LTT Y DID FINALLY SEE HIS TFC.