Good concrete tank management is a pre-requisite for profitable fish farming and how best we manage our concrete tank as a farmer or intending fish farmer should be of utmost importance.
Concrete tank which is one of the most common holding facility for fish culture in Nigeria especially in areas where the soil cannot hold water and this tank is of two common type:
- – Surface concrete tank
- – Submerged concrete tank
The sub-merge concrete tank as shown in fig: 1 & 2 below, have an advantage of the walls getting more support from the mother earth which also assist in quick regulation of water PH and temperature within a short period of time.
The surface concrete tank as shown in fig: 3 & 4 below, whose wall does not get more support from the mother earth like the sub-merge concrete tank, but it is less expensive when compare with the sub-merge concrete tank in terms of construction cost.
The management system between the two type of concrete tank are almost the same but the only difference is that the sub-merge concrete tank need more excavation of the mother earth.
Concrete tank management start from architecture through to construction which include materials use, foundation, tank facility layout (water-inlet, water outlet, excess water spillage, harvesting basin etc.), drainage and finishing.
Architecture: Before you can construct an IDEAL concrete tank as a fish farmer or intending fish farmer (ideal tank is a tank that have all the functionality or facility layout such as water inlet/outlet, excess water spillage and harvesting basin), it is advice to seek the service of a fisheries consultant to present to you on how you want your concrete tank to look like either digital view (3D, Visio etc.) or analog view (pen and paper), this is important because:
- You will be able to make a prepare plan in terms of costing of materials (Number of blocks and cement, length/size of PVC pipe for water inlet/outlet etc.).
- You will be able to view how the tank facility (like water inlet/outlet, harvesting basin, excess water spillage) layout or going to be position.
Construction: When constructing an IDEAL concrete tank, the following procedures need to be stick to:
- It is advice that you use quality materials to avoid re-buying the same material again for the same purpose.
- The ratio of block: cement should be one bag of cement to produce maximum of (6″) 30 blocks, the stronger the block, the better the durability.
- Dig the foundation and fill up the base with concrete cement.
Note: using of palm canal shaft or periwinkle shell is not advisable because it can lead to concrete tank wall collapsing.
- Use a blind block (block without hole) or when using a hollow block fill the holes with good mixture of cement and or granite.
- Arrange the blocks in layers to get to the desired height with good mixture of cement/sand or granite to hold the block firmly to avoid horizontal or vertical linkage.
- Install the tank facility (water inlet/outlet, excess water spillage and harvesting basin) and layout.
In conclusion when the above procedure is done properly, the following are some of the benefit that will save you more maintenance cost in the future:
- Easy water flow into the tank through the water inlet
- Total water exit out of the tank during total water draining through the water outlet.
- Easy fish harvest during total harvest through the harvesting basin (Less stress for fish).
- Easy excess water exit through the excess water spillage during tank over flow (preventing fish from escaping during tank over-flow).
With the quality materials use, strong foundation and propare installation/building of the tank, you are sure of less maintenance cost and longer life-span for the tanks.
Nicholas Izekor is an Aquaculture Trainer at The Ark Shore Konsults (T.A.S.K.). He holds a Bachelor’s degree in Fisheries Management from the University of Benin, Nigeria.