Water is the single most important ingredient in an aquarium. If it is polluted or toxic your fish will suffer. Remember: Good Water + Good Food = Happy, Healthy Seahorses. When your water quality is poor your horses will stress, stressed seahorses can become vulnerable to parasites and pathogens.
Seahorses, as the name suggests live in seawater. They do survive in varying levels of salinity, but it is best to keep your salinity (measurement of salt content) as close as possible to the ocean.
When adding new water never use a bucket that has had soap or detergent in it. Purchase a new bucket and keep it only for use with your aquarium.
If you can access clean seawater from the ocean, then do so. Ensure that the place you are collecting from has no sewerage, storm water or river outlets nearby and there are no visible algae blooms. Some aquarium shops sell ocean sourced water for convenience.
Making Sea Water: Most aquarium shops sell marine water additives. Do a bit of research into the various brands available. Read all the directions carefully and follow them. Always start with de-chlorinated fresh water in your clean bucket and DO NOT use household salt.
Water Quality Monitoring: There are six main tests you need to perform on your tank on a weekly basis. A small chart or record book helps you to notice fluctuations. It is best to test your water quality at the same time of day. For example if you perform your first tests late afternoon/night time, ensure future testing is not done in the morning, things like light can have an effect on your test results. It is not important what time of day you do your testing, but keep the time of test consistent.
Test Kits: For most of your water tests the simplest and most economical test kit is a color-metrics salt-water test kit. These kits work by taking a small sample of your tank water, mixing with special reagents (either in drop or tablet form) and after a time period, color matching to a color chart. You will need to read all instructions carefully and ensure you follow them correctly. They must be salt water test kits.
Temperature: Seahorses must be kept at the recommended optimum keeping temperature.
An aquarium thermometer provides an easy, cheap effective form of measurement. For ease a submersible or floating thermometer can be added to the tank to see at a glance.
Salinity: The main cause of change in this reading is evaporation e.g. using a heater and not having a lid or hood on your aquarium. It is the water that evaporates not the salt.
The cheapest method of measurement is via a hydrometer. This measures the specific gravity of your water. Always keep your seahorses as close as possible to the optimum salinity requirements. When your salinity is too high you need to add de-chlorinated fresh water, if you add seawater you will not change the salinity. Only ever make small adjustments (<10% of total volume).
pH (acidity or alkalinity of water): Seahorse excretions, decaying food etc., cause changes in your pH. The optimum pH of seawater is 8.2 Color-metric test kits are probably the easiest and cheapest. High pH is alkaline and low pH is acidic. Never change the pH by more than 0.2 in any 24-hour period.
Readings of between 8.1 and 8.3 don't cause major stress, but if your pH is changing there may be a reason. Test for Carbonate Hardness (kH) this could be your problem.
Ammonia (NH3 /NH4+ ): Ammonia is the toxic waste produced by your seahorses when they excrete. This is a soluble toxin, you can't see it, although your water will look clear, it could be poisoning your seahorse. This is a MUST test EVERY week. Your reading should be 0.0 ppm at every test. The best way to reduce ammonia levels is to do 20-50% water change to your tank.
Nitrite (NO2- ): Nitrite levels in an established aquarium should always remain below 0.25 ppm.
Nitrite spikes (or high readings) as they are commonly called, occur when you are establishing your biological filter as part of the nitrogen cycle.
If you are experiencing levels of nitrite you may have damaged your bacteria that live on your filter medium (gravel, glass, coral, sand bio-balls etc). To reduce nitrite levels a 20% - 50% water change is recommended.
Nitrate (NO3- ): Nitrate is the waste material produced by the second group of nitrifying bacteria after converting the nitrites. Marine tanks should have levels of <30 ppm. To reduce levels of nitrates in your water perform 20% to 50% water changes depending on the level of nitrates
Phosphate: This is a by-product of fish and decaying organic matter like dead algae or uneaten food. Excessive phosphate levels promote the growth of algae. In new aquariums the test results will usually be nil or less than 0.1 ppm
Carbonate Hardness kH: The measure of dissolved carbonate and bicarbonate ion concentrations. The Carbonate Hardness is an important measurement. Strong carbonate hardness can mean a very stable pH. Marine aquariums should have a kH reading of 80-120 ppm. The carbonate hardness levels deplete as a result of the breakdown of waste products by bacteria via biological filtration. Carbonate Hardness testing would be the next test to do when pH test results fluctuate.
Maintenance of your water and tank Ensure you unplug all your filters and heaters prior to any cleaning activity. Remove any visible solid waste by siphon hose, be careful and don't move your gravel around too much this can upset the good bacteria.
Weekly - Do your water quality testing, clean any algae build up on the glass and remove about 5% to 10% of water. Replace this water with fresh seawater (either sourced from the ocean or made from aquarium sea salt).
Monthly - It is advisable to remove your hitching posts and decorations and give a clean in clean sea water to remove any algae build up
Hygiene is a critical issue with aquariums so NEVER use any detergents or add foreign water (from another tank e.g. the water that comes in the bag when you purchase your seahorses) to your tank. It may contain nasties that you don't need added to your tank.