Cynoff WP is a wettable powder, so it leaves behind a white residue that is noticeable on darker surfaces once dry as it reverts to its powder form, just adhered to surfaces. It is not labeled to be used on floors as a broadcast, only around the rooms along baseboards, cracks and crevices etc.
It is normal to see the nymph roaches after spraying. Only the insects that actually come into contact with treated areas will be killed by Cynoff. Basically you have killed off the larger adult roaches with Cynoff WP but you still have egg cases that are hidden away and they will continue to hatch and you will see the smaller nymph or baby roaches. We recommend that you use an insect growth regulator such as Gentrol IGR to help halt the growth of the juvenile roaches. By halting the growth of the roaches you will be able to stop them from reaching sexual maturity which in turn will stop the prodution of new eggs. We also recommend that you use a roach bait gel such as Advion Roach Bait Gel to get rid of those roaches that hide in areas where cannot spray such as wall voids, cabinets, drawers and cupboards. You can purchase these two products together in our Roach Control Kit #1.
Ants can also be controlled with a bait product. Advion Ant Bait Gel can be applied in areas where you see ant activity. The ants will eat the gel and return to the colony where they will feed the gel to the other ants, effectively wiping out the entire colony. It is very important to avoid spraying Cynoff in places where you apply the roach bait gel or the ant bait gel to avoid having the insects reject the bait.
Cynoff WP cannot be used in a septic system nor can any other insecticide we carry be used down drains. Roaches would only be coming from the drains if there is a crack in the pipe allowing them to come in. You would generally only see roaches coming from drains after they have gone down to get water. For roaches in a home we would recommend one of our Roach Control Kits and also have a great guide that explains the best treatment to eliminate them.
Cynoff WP is not labeled for bedbugs so we cannot recommend you use it for bedbug control. For more information on a successful bedbug treatment program, please review our article on How to Get Rid of Bedbugs.