I found this on another forum and thought it may prove useful if you are having problems with cloudy beer.

Its originates from the book by R. Douglas Bailey, The Brewer's Analyst, 1907

Brilliancy

All beers should be perfectly brilliant and free from suspended bodies. When a beer is not bright, some of the causes can be ascertained by the following methods.

(1) Filter the beer through an ordinary filter paper. If the beer filters bright, the trouble is due either to the presence of

(A) Normal yeast, or
(B) Wild yeasts.

If the beer does not filter bright, proceed with test 2.

(2) Pour upon a plate a little of the beer, add a drop or two of iodine solution. If the beer gives a blue reaction, it is due to the presence of starch (C). If the beer does not give a starch reaction, proceed with test 3.

(3) Warm a sample of the beer in a test-tube or beaker. If it becomes brilliant, the trouble is due to the presence of glutinous matter or hop resin. To find which of these one has to deal with, proceed with test 4. If the beer remains cloudy, then proceed with test 5.

(4) Pour a little of the beer into a test-tube or beaker, and add a little ether. If the beer remains cloudy, the trouble is due to the presence of glutinous matter (E). If the beer becomes clear, the trouble arises from the presence of hop resin (F).

(5) Obtain a deposit from the beer by means of the centrifuge, and examine the deposit under the microscope.

The trouble may thus be traced to the presence of Saccharobacillus Pastorianus, Sarcina, or other bacterial organisms ; or to the presence of wild yeasts or an excess of normal yeast.

It often happens that the cause of the cloudiness in beer is due to a combination of simple causes, thus--wild yeasts combined with bacteria; starch combined with bacteria. In the cases of wild yeasts combined with bacteria, beer does not take finings, or takes them badly. In cases where starch exists the fermentation is very sluggish.

Simple tests (apart from the last one!)