DPD 1 Test Tablets - 250 Tablets

Palintest DPD No 1 reagent tablets, boxed in 250s, for reading free chlorine (and free bromine) on a comparator or photometer. These are rapid-dissolve tablets for instrument testing, not dip strips, so the result is a measured figure rather than a colour-chart guess. Pair with DPD No 3 tablets when you also need total chlorine.

• Reads free chlorine on a comparator or photometer as an actual number.
• Reads free bromine too, through the standard DPD cross-reaction.
• Dissolves fast when crushed into the sample cell for a clean colour.
• Gives the repeatable accuracy that colour-chart strips cannot match.
• Works alongside DPD No 3 tablets when total chlorine is also needed.

Price

£24.95

How to use

1. Rinse the test cell with the water you are about to test.
2. Fill the cell to the 10 ml line with a fresh sample.
3. Drop in one DPD No 1 tablet without touching it with your fingers.
4. Crush and mix the tablet until it has fully dissolved.
5. Read the result on the comparator disc or photometer straight away.
6. Record the free chlorine (or free bromine) figure in your log.

Frequently asked questions

What does DPD 1 measure?

Free chlorine, the portion of chlorine actively sanitising the water. It also reads free bromine via the same DPD reaction.

Is this a dip strip?

No. These are rapid-dissolve reagent tablets for comparator or photometer testing, which gives a measured figure rather than a colour-chart band.

How many tablets in a box?

250 tablets, so 250 free chlorine or free bromine tests.

What is free versus total chlorine?

Free chlorine is what is still available to sanitise; total is free plus combined. DPD 1 reads free; DPD 3 gives total.

How do I get combined chlorine?

Run a DPD 1 test for free, then a DPD 3 test for total, and subtract free from total. The difference is combined (used-up) chlorine.

Which tablets pair with these?

DPD No 3 tablets. Run both to get free and total, then work out combined. Phenol Red tablets cover pH.

Will it read bromine?

Yes. DPD 1 reads free bromine through the same reaction; scale the chlorine value by about 2.25 for a bromine figure.

Why tablets over strips?

Strips give a rough colour band; DPD tablets on an instrument give a repeatable number, which is what commercial logs need.

What sample volume?

One tablet per 10 ml sample in the test cell.

Colour too dark?

The residual is over range; dilute the sample 50:50, retest and double the reading.

How long do tablets last?

Stored cool, dry and sealed they keep well; replace any box that has gone soft or damp.