I've found during low clear conditions over the last few summers that the most consistant sport with barbel has come while using a small hookbait that matches, for size at least, any freebies i might be offering.
If you're going to fish with an 8 mm boilie on the hook then i would feed 8mm boilies. My own preference is for a single 6mm elipse pellet fished over a bed of mainly hemp, with a few hookbaits mixed in. I use the 'mega' hemp which is roughly 6mm grain size, not the ridiculously expensive and pathetically small stuff you can buy in tins from the shop.
My line of thinking is that by presenting a bait that is similar to the freebies it is harder for the fish to pick out the hookbait. So many times i watch others presenting a 12mm pellet over hemp, or a 15mm boilie over micro pellets - they sit biteless all day, only starting to get indications as it gets dark. Some even convince themselves that the barbel will not feed during the day - it's that bad! In my opinion the main reason they aren't catching is because they are making the hook bait so obvious it is easy for the fish to pick out and avoid.
Perhaps more important than the bait is the way in which it is presented. In low clear conditions, and especially on stretches that recieve a fair amount of pressure, the barbel will be well aware of a badly presented bait. Being able to watch barbel feeding allows you to quickly learn what they will and will not put up with regarding tackle in the swim. For those of you who haven't had the pleasure - the scariest thing for a pressured barbel is the mainline entering the swim. It doesn't seem to matter what it is either, mono or braid, clear, camo or even red ( for my mate Jerry
). The point at which it rises from the river bed to the rod tip will be avoided like the plague by most barbel. This is why those fishing rods high in the air, again sit biteless during daylight hours. Using a simple running lead or feeder set up, bites can be encouraged during daylight hours by simply using a longer hooklink ( say 6'+ ) as all you are doing is trying to put the hookbait as far away from the point where the line rises from the bottom as possible. Keeping the rod tip low to the surface also helps to flatten the line down. I must say that i've found the long hooklink approach to be rather ineffective at converting pick ups to hooked fish. It does work, but all those little taps and plucks are often barbel getting away with picking up your bait and ejecting it when they realise all is not well. The solution, if the swim allows, is to go down the carp anglers route of short hooklinks, rig tubing and backleads. Definately not recomended in rocky, snaggy swims - but the more you can do to disguise your rig, the more you will catch.
