Liquid gypsum vs calcium thiosulfate
Real gypsum at 19.55% calcium. Clear liquids declare 6%.
Gypsum is a mined rock that barely dissolves, so a true liquid gypsum is cloudy and settles. A clear liquid declaring 6% calcium and 10% sulphur matches calcium thiosulfate, a manufactured salt. Ours is the rock, ground fine.
£19.99 1 litre
Choose Liquid Gypsum★★★★★ Shop rated 4.95/5 from 513 reviews. Free UK delivery over £40. Dispatched in 1 to 2 working days.
- Three times the calcium per litre of the clear liquids, so a lower cost per square metre.
- Sulphur in the form plants use straight away. Thiosulfate has to be converted in the soil first.
- No change to soil pH. Neither bottle fixes packed soil or drainage.
Cost per square metre
| Bottle | Price | Lawn covered | Per m² |
|---|---|---|---|
| Dr Forest 1 litre | £19.99 | 100 m² at 10 ml per m² | 20p |
| Eutrema 1 litre | £17.99 | 25 m², about 40 ml per m² | 72p |
| Dr Forest 5 litres | £72.99 | 500 m² | 15p |
| Eutrema 5 litres | £29.00 | 125 m² | 23p |
A 50 m² lawn takes 500 ml of ours or about 2 litres of Eutrema. Eutrema prices and coverage from eutrema.co.uk, October 2026; ours 27 Oct 2026. Eutrema is a trademark of its owner; Dr Forest is not affiliated. Pack sizes: price page.
Side by side
| Dr Forest Liquid Gypsum | Eutrema Liquid Gypsum | |
|---|---|---|
| What it is | Calcium sulphate: natural quarried rock, ground | Figures match calcium thiosulfate, a manufactured salt |
| Declared analysis | 19.55% calcium, 15.31% sulphur | 6% calcium, 10% sulphur |
| In the bottle | Cloudy; shake 30 seconds | Clear |
| Clay-soil trials | Run with calcium sulphate | Not run with thiosulfate |
Eutrema column from its published listing; we have not analysed the product and its label is the final word. Trials: product page, The Science.
Which to buy
- Clay that clouds a glass of rainwater, a lawn you cannot dig, calcium without raising pH: ours.
- A drip line that needs a clear liquid: calcium thiosulfate, under its own name.
- Water sitting all day in a 30 cm hole: neither. That is drainage.
Common questions
Is Eutrema Liquid Gypsum real gypsum?
Not on the published numbers. Water holds about 2.5 g of gypsum per litre, so a clear liquid cannot carry 6% calcium as gypsum. Gypsum also has more calcium than sulphur; theirs is the other way round.
Is calcium thiosulfate a bad product?
No. It is an established farm fertiliser, sold as CaTs, and a good way to run calcium through a drip line. It is simply not gypsum.
Why does yours settle?
Ground rock in water, nothing synthetic to hold it up. Shake 30 seconds, mix fresh, use the same day.
Gypsum you can see in the bottle
19.55% calcium, 15.31% sulphur, no pH change. 10 ml per litre on lawns, 15 ml on clay.
£19.99 1 litre · 5 litres £72.99
Free UK delivery over £40. Dispatched in 1 to 2 working days. Packed and posted from Stockport.