Odour Control Fluid for Portable Camping Toilets UK: OLPRO Promises to Kill Foul Odours, and Eight Recovered Reviews Never Confirm It

Eight Reviews Is All We Could Recover, and Five Say Nothing

Start with what we are working from, because it changes how much weight any of this can carry. When we collected this on 2 September 2026 the listing showed a 4.4 star average from 131 ratings. What we could actually pull off the page is eight review cards, taken from Amazon's Top reviews from the United Kingdom widget. That widget is a curated selection: not the most recent, not random, and not the full record. Eight is what could be recovered, not what exists.

All eight are United Kingdom reviews and all eight are verified purchases, so nothing here needs translating and no overseas buyer's experience is being passed off as a British one. The star spread runs five at five stars, one at four, one at three and one at one, which averages 4.12. We are not going to make anything of the gap between 4.12 and the listing's 4.4, because eight curated cards cannot tell you whether a 131-rating average is drifting.

What matters more is how thin most of them are. Five of the eight offer a verdict and no detail behind it. Four of those five run to seven words or fewer, two of them being “Works well” and “Not bad at all....”. The fifth is longer and written entirely in capitals, but it goes no further than saying the bottles do what they are supposed to and are good value for money. Real buyers, real five-star ratings, and no observation about odour, waste breakdown, dosing or how long a bottle lasted. Three of the eight actually describe using the product. This review leans on those three and counts the other five rather than quoting them.

The Blue One Is the One That Has to Work

OLChem is the blue bottle and it is the one doing the work most people are buying for. The label reads WASTE TANK ADDITIVE, 2Ltr., Formaldehyde Free, Made in Britain. The listing image beside it puts the promise in two lines of capitals: BREAKS DOWN WASTE. KILLS FOUL ODOURS. Amazon's bullet points make the same claim in softer words, saying OLChem is designed to break down waste quickly and help control unpleasant smells in the waste tank.

The number that actually helps you plan is not in the bullets at all. It is printed on one of the listing images: 70ml dose for a 10L waste tank. Nowhere in the written description does OLPRO tell you the dose, which is a strange omission on a product whose value depends entirely on it. Bullet five gets as far as add the recommended amount and stops.

Do the arithmetic and a 2 litre bottle holds about 28 doses of 70ml. If your cassette or portable toilet holds somewhere near 10 litres of waste and you empty every couple of days on tour, one blue bottle covers a lot of weekends. A bigger tank means more fluid per fill and fewer doses, so scale it to your own unit before you compare a twin pack against a single large jug of something else.

Formaldehyde-free is the other headline and it is stamped on the bottle rather than living only in the sales copy. The listing frames it as safer for septic systems and eco-sensitive disposal points. Treat that as OLPRO's own claim rather than a certification: the listing text names no standard, test or approval body, and neither does the front of either label in the listing photographs. Those photographs never show the back of a bottle, so we cannot speak for the small print there. For what it is worth, the listing's own product details give the scent as almond. One oddity worth knowing: the labels say Made in Britain, while the listing's country-of-origin field gives China. We cannot reconcile those two and we are not going to pretend either one settles it.

One thing neither the bullets nor the images tell you, and it matters more than the dose: treated waste goes to a designated chemical disposal point, not into a grey water drain, a storm drain or a hedge. Sites keep the chemical point separate and away from fresh water for a reason. If you are not on a site, work out where you are going to empty it before you fill it.

Two of the Eight Talk About Smell, and Neither Is a Compliment

This is the finding the article turns on. Not one of the eight reviews we recovered says the odour control worked. Two mention smell, and neither is a compliment.

The three-star review, from kirsty lowry, is the more useful of the pair: “Does the job but doesn't smell great when in use. Ended up using more than necessary to cover smells so not great value for money.” We spent a while on whether that first clause means the chemical's own scent is unpleasant or whether waste smell was breaking through, because those are different complaints. The second sentence points hard one way. The three-star reviewer was using more of it than they felt they should have needed, in order to cover smells, which means there were smells there to cover. We read it as odour control coming up short in use, not as a quibble about fragrance.

The one-star review is blunter about why. Utrinque Paratus III writes: “There's a reason it's cheap. It's over 90% water with just a hint of colour and smell. You're buying water.” He does not say how he arrived at 90%, and it is not a figure anyone can check, so it stands as one buyer's impression of the strength rather than a fact about the formula. He lands where kirsty lowry landed, from the opposite direction: that reviewer needed more of it than expected, while he thought there was too little in the bottle to start with. Two of eight, agreeing without agreeing.

One note for completeness, because it is the nearest thing to a positive smell comment in the set. foxy's four-star review opens with “Great sent”, and we cannot tell you which word was meant. Scent is one reading. Send, as in dispatch, is another, and this set does carry that praise: one review is titled “Fast delivery” and another praises the seller. An ambiguous word is not evidence, so we count it in neither direction, and the finding above stands.

The Pink Bottle Goes in the Water You Flush With

OLRinse is the other half of the pack and it goes somewhere completely different. Its label reads FLUSH WATER TANK ADDITIVE, 2Ltr., Fresh Fragrence, which is the bottle's own spelling, and Made in Britain like its partner. The listing image promises FRESH FLUSH SMELL. KEEPS WATER CLEAN. Amazon's bullet adds that it helps keep the flush tank and bowl clean and leaves a fresher scent after each use.

The dose is the same: a second listing image reads 70ml dose for a 10L flush tank. So a full cycle on a 10 litre toilet costs 70ml of blue in the waste tank and 70ml of pink in the flush tank, and on a 10 litre pair of tanks the twin pack gives you roughly 28 of those cycles. Very few real toilets are 10 litres in both halves, though, so check yours before you treat that as your number. The portable flush toilet we reviewed, a Thetford Porta Potti, carries a 15 litre flush tank, and its listing gives the waste tank as 21 litres in two places and 12 litres in a third. At 21 litres that is about 19 pink doses against about 14 blue; at 12 litres it is about 19 pink against about 24 blue. Either way the two bottles do not empty in step, so do not buy the pack expecting them to.

It also tells you which toilets this is aimed at. The target is a portable flush toilet with its own flush tank on top and a detachable waste tank underneath, the sort of unit we went through in our review of a portable flush toilet for tent camping. One buyer confirms the fit in the plainest way available: the only reviewer in the eight who names their toilet titled the review “TOILET CHEMICALS FOR A PORTER POTTY”. Motorhome and caravan cassettes work the same way, with the flush water carried on board. If your setup has no flush tank at all, which covers most bucket toilets and dry separating toilets, half of this pack has nowhere to go and you are better off buying a waste tank fluid on its own.

The Blue Ends Up Where You Did Not Want It

Two of the eight reviews raise the same practical gripe, and it is the only purely mechanical complaint two buyers here independently raise. The blue gets out of the bottle and onto things it was not meant to reach.

foxy, at four stars, is otherwise content, and this is the one old review in the set, from November 2021: “Great sent and does the job, however I do find it hard to pour without spilling the blue”. kirsty lowry's three-star review closes on the consequence: “Very blue and dies everything it touches”. Neither says whether the marks came out, so we will not guess at that.

The listing images make the point without meaning to. One shows the flush tank filler, a round screw cap sunk into a moulded recess on the top half of the toilet. Another shows the waste tank's pour spout on the bottom half. Those are the two openings you are aiming 70ml of strongly coloured fluid at, from a 2 litre handled jug.

Two of eight is not a fault cluster and it is no reason to walk away. It is a reason to decant rather than free-pour. Nothing on the listing or in any of the images shows a measuring chamber built into the bottle, so assume there is not one and budget for a cheap measuring cup or a funnel.

Who Should Pay More, and What For

If you keep a portable toilet for occasional use and empty it every day or two, six of the eight buyers rated this four stars or better, and the physical offer is straightforward: four litres across two bottles, both tanks covered in one purchase, formaldehyde-free and Made in Britain on the label, dosed at 70ml per 10 litres. What the reviews do put pressure on is how far that goes. One buyer says they got through it faster than they expected to, and another calls the fluid too dilute to be worth the money. Plan around the dye, though. Two of the eight raise it, and one of those two sits inside that six.

If smell is the actual problem you are trying to solve, this set gives you nothing to lean on. Warm weather, a tank left standing a few days, a toilet tent with no through-draught: no reviewer here reports the product holding up in any of those. The one buyer who takes on strength directly names a pricier brand as the one he wishes he had stayed with: “I should have stuck to Elsan at two and a half times the price but at least I'll get more than a weekend out if it.” Read literally, the it in that last clause is the Elsan, so he is saying the dearer fluid lasts longer rather than measuring how long the OLPRO lasted him. We will not make a figure out of it, but the direction is not subtle.

So, if odour control in a warm tank is your priority rather than a bonus, the obvious alternative is Elsan Blue Toilet Fluid. It is what that one detailed critic named, and its listing describes it as suitable for all chemical toilets and cassettes and calls it non-staining, which speaks to the staining half of the complaint two OLPRO buyers here raise. Then three caveats, and the third is the one that decides it. You will need a separate rinse fluid for the flush tank, the errand the twin pack saves you. Elsan's listing text prints no dose rate, so unlike OLPRO you cannot work out before you buy how far two litres goes. And Elsan Blue's Amazon listing carries a product safety warning that the OLPRO listing does not carry at all: causes serious eye irritation, causes skin irritation, harmful if swallowed, harmful in contact with skin, may cause an allergic skin reaction, may cause respiratory irritation, suspected of causing cancer. If the formaldehyde-free label was part of why you were looking at OLPRO, read that warning in full before you buy.

Three Usable Reviews, and What They Are Worth

We score this 3.6 out of 5, and the working is short. Six of the eight buyers rated it four stars or better, so there is no failure cluster and no reason to tell you to avoid it. But five of those eight say nothing at all, and a score cannot rest on ratings that carry no observation behind them. Of the three reviews that describe using the product, two say it is too weak for the money and two flag the blue dye getting where it should not, with one reviewer counting in both. That is what we are scoring, and it lands below the 4.4 on the listing.

The reminder that goes with the number: 4.4 is a lifetime average across 131 ratings, while our eight are what we could recover from a curated widget on the product page. They are not the most recent eight, not a random eight, and not the whole record. If you can see a longer run of reviews than we could, weight them above ours.

Buy it if you want both tanks covered in one purchase, you empty regularly, and formaldehyde-free matters at the site you use. Spend more elsewhere if the smell is the thing you are actually trying to fix, with the warning above read first. On value the eight split evenly among those who mention it: two call it good value, two say it is not, and the other four do not raise the subject. Just do not buy it expecting the capitals on the listing image to be a finding rather than a promise.