We have presented the new Mares Hydro backpack buoy in our X-rays column. Definitely it is a great product, which goes beyond the already excellent Subea SPF 900 backpack buoy. The latter is the winner of the 2023 Best Choice by Apneapassion in the Accessories category. We have now tested the Mares Hydro backpack buoy, and here are our true results.
Internal storage space
There is really plenty of internal storage space in the Mares Hydro backpack buoy. One must release the two clips of the internal straps that keep the buoy in shape when in the water. We inserted one pair of 6 mm pants and two jackets, 6 and 8 mm of the wetsuit, and a 2 litre water bottle. Indeed, there was still a lot of space.
The zip is of good quality. It isa little bit hard to open and close, but this is normal since it is a special solution to obtain a water tight system. An elastic band helps keeping it well closed. Mares suggests putting some light grease every now and then to keep the water tightness of the zip. The front mesh pocket is useful to to objects which are water resistant, such as our light torch. Some people use such pocket to position the GPS instrument, useful to find our spearfishing spots.

Positioning of spearguns and fins
The positioning of the spearguns is easy, one per side. The muzzle and barrel are inserted in the upper adjustable nylon strap, while the lower one has a very useful fast release system. A steel hook can by quickly connected or detached from the nylon strap. Such solution permits to pass the strap inside the hilt of the speargun blocking it in the best way, and avoiding it to slide down. It is better to insert the release mechanism safety system to avoid the shaft to be released (even if, of course, the speargun is not loaded) and lose it position.

If we connect pneumatic spearguns to the Mares Hydro the connection is perfect, and so it is if we position sling spearguns. In this case we simply need to take care of passing the upper strap around the rubber bands. A small issue comes when the sling speargun is very long, for example a 110 cm, as the upper strap cannot be passed around the rubber bands. In this case the upper strap, even adjusted at the minimum length, is still a bid wide. The speargun is kept in position, but moves a little. We think Mares could and will modify this measures quite easily.

The blades are inserted in the front mesh pocket. An adjustable strap runs around the blades on the side of the foot pockets keeping the fins perfectly in place. It has also a small and very useful safety whistle on it.
Shouldering the Mares Hydro

Shouldering the Mares Hydro backpack buoy is easy and comfortable. The shoulder straps are easily adjustable both in the upper and lower part. An additional front nylon strap keeps the Mares Hydro well blocked also on the chest. Walking is very comfortable with the backpack buoy on the shoulders. This means you can move along extended and eventually rough paths with no fatigue or discomfort. The only equipment you will not be able to put in the Mares Hydro is the weight belt with weights, which of course you will put around your waist.
Equipment out and clothes in
Once reached the sport is it quick and easy to take out the equipment from the Mares Hydro backpack buoy and put in our clothes, shoes, mobile phone and wallet included. It will all be safe and dry. You will also release the shoulder straps opening the velcro and releasing the lower hooks. The shoulder straps will also be positioned inside the backpack.


The only small aspect which makes this process just a tiny bit less easy is that we will need to connect the two internal Nylon bands. This aspect is key to keep the Mares Hydro in the correct shape which will also determine a great balance in the water. This is a net improvement compared to the Subea SPF 900 backpack buoy. The latter, in fact, has to be balanced with weights in the lateral pockets, and is anyway a little unstable as the inferior surface is slightly convex.
In the water
Great balance

Insert the tall mast and big dimensions signal flag laterally on the Mares Hydro and simply throw the backpack buoy in the water. It will keep perfectly the correct horizontal position, and will not fall on its side even with strong wind. We tested that in an extremely windy day in the North of Sardinia, with the famous in the area Mistral wind.
The balance of the Mares Hydro is so perfect, even with only one speargun on the side and one in our hand. Also, the tall mast and big signal flag to not determine a capsize of the backpack buoy.
Surface transfers

We will have to lay on the Mares Hydro positioning ourselves in the correct position. This means centrally, and well on the buoy to have a good balance and be able to fin properly and efficiently. Once this is done, honestly the Mares Hydro works perfectly. The mast of the signal flag remains under the right armpit and so in not in the way. The transfer speed is not exactly the one of a rigid dive board, but the advantages of the Mares hydro compared to a rigid solution are so many that indeed it is the best choice for many uses.