Taking the mayhem out of marine fish keeping
EQUIPMENT FOR YOUR MARINE TANK
Pumps and powerheads
Various other pages have already discussed the need for, and benefits of, some sort of water flow in your marine tank. Depending on the livestock you wish to keep you will be aiming for a flow rate somewhere between 20x and 40x water volume turnover per hour.
There are literally hundreds of different powerheads to chose from and your final desicion will be influenced by your budget. If you type marine aquarium powerheads into google every make available will come up so here I will just touch on some of the things to look out for.
Every powerhead will come with some sort of rating of litres of water moved per hour. When you are considering your tank filtration you can add up the combined litres moved per hour to work out which powerheads are suitable for your particular flow. For exammple if your tank is 400 litres and you are keeping a simple softy tank (therefore aiming for 22x turnover) you will be looking for 2, 3 or 4 powerheads that combine to give (400x22) 8,800 litres per hour. As already mentioned on the 'Flow in your marine tank' page, your tank inhabitants will be better of with a few smaller powerheads rather than one large one which will just blast them into obliviion.
Directional powerheads are useful as you may want to be able to direct different powerheads to different surfaces in your marine tank. For example I point two of the rear powerheads at the front glass in the middle of the tank but the two front powerheads point to each other.
Make sure your powerheads are safe for saltwater, you don't really want any metal elements in your marine tank which could, over time, leach nasties into your water. many powerheads are designed to be submerged inside the aquarium and come with a magnet that fixes it to the glass from the outside. Whereever you place your powerheads make sure you can reach them easily for routine maintenance. They will need regular cleaning to ensure their perfomance isn't compromised by a build of general aquarium detritus, algae and such like.
Always go for powerheads with some sort of protective cover or grill over both the intake and outflow. This is particularly important if you decide to keep something like an anemone in the future. Some marine organisms will find their way into your powerhead if it's not protected and the outcome is not pretty.
Some marine fishkeepers like to use wavemakers to try and more accurately reproduce the more random, varied flow of the sea. Wavemakers work by turning pumps on and off via a control and many people believe their aquarium is healthier for it. Constantly turning powerheads on and off can, however shorten their useful life and it's worth noting that not every powerhead is suitable for being run on a wavemaker.
Some of the kit you will buy will come with pumps suited for that purpose such as protien skimmer. The same general guidelines apply, protect intakes and always make sure the kit is suitable for use in saltwater.
Pumps and powerheads
Powerheads with directional flow will give you much more flexibility when it comes to positioning some of your livestock
Always make sure any intake and outflow of all powerheads is fitted with some sort of guard to reduce the chance of any tank inhabitants beocoming fish soup.
Pumps - in a nutshell
Use a few pumps of different outputs to achieve your combined flow rather than one large one
Flow is important in any marine tank to make sure your filtration is working properly
Maintain your pumps and powerheads regularly otherwise they will reduce the useful flow within your marine tank (therefore compromising the filtration) without you noticing
Although it's tempting to hide powerheads away behind rockwork or tuck them at the very back of a rock wall to reduce the chance of any dead spots remember that you will have to access them fairly regularly
Some types of pumps can be controlled by wavemakes which randomise the flow in your marine tank, these seems to be appreciated by many different tank inhabitants.