Two of the most under-tested and maintained parameters in an aquarium system are pH and KH! Hydrogen potential and carbonate hardness respectively. I would lump nitrates in that group but many are aware that is an important chemistry and is frequently tested for. This short article will give you a little food for thought when attempting to solve some chronic problems or perfect your aquarium.
PH fluctuates considerably mainly because of the biological/physiological parameters in your aquarium. The goal is to keep your pH from fluctuating during a normal diurnal (24 hr) cycle by maintaining a refugium, buffering with supplements, or both. By raising the alkalinity, or buffering capacity, and/or reducing the effect of CO2 on your system you can defend against these fluctuations. A refugium is basically a secondary aquarium with massive macro-algae growth that functions under low lighting when your main aquarium is “sleeping” (i.e. main lights are off). Why a macro-algae garden you ask? I’ll answer with a question. What do fish breathe and what do plants breathe? Fish breathe O2 and “exhale” CO2, plants – or algae in this case, the only true saltwater plant is the mangrove tree – “breathe” CO2 and “exhale” O2. Now think about what happens when the lights go out in the main aquarium. Live rock, coralline algae, and macro-algae all stop their photosynthesis (reduction of CO2 and production of O2) which drives the production of chlorophyll, a plant’s food source. Only problem with that is, the animals in the aquarium continue to “exhale” CO2 even when the lights are off which then starts to affect pH. CO2 acts like and acid and reduces pH – or the “hydrogen potential” – of an aquarium for however long the lights remain off. The concept of the refugium continues the CO2 reduction thereby keeping pH levels stable. With a good crop of macro-algae some systems may have no dips at all and keep a constant 8.2 pH.
Alkalinity buffers can and, in my opinion, should be used in all systems since it is an excellent guard against potential problems like, for example, the asexual flush of all chlorophyll that very rarely happens to crops of macro-algae. I’ve only seen this happen once in my years of aquarium care. It’s actually pretty amazing. Within seconds 15 to 20 pounds of macro-algae will turn an opaque tan color as it dumps all its chlorophyll and will turn an aquarium a bright green. If you have a good skimmer it takes around 2 hours for the green to be removed. In a case like this you no longer have a photosynthetic crop of algae to continue reducing CO2 at night. Buffers can guard against pH changes until more algae is acquired and a new crop is established.
Carbonate Hardness (KH) or “calcium carbonate concentration” is another water parameter that really needs close attention, especially in reef systems. Depending on the calcium demands of your aquarium, you may or may not have to add additional supplements to maintain calcium levels for good coralline algae or coral growth. Your stony corals are especially sensitive since they are perpetually “building” and low or neglected levels can actually cause a die-off. Make sure you use the appropriate liquid test kit to evaluate your calcium levels. If low, find a good calcium buffering system like Kent Marine’s Tectra Tech CB A & B solutions that are for both alkalinity and calcium maintenance.
Keep and eye on Nitrates, pH, and KH in your system as these three do affect each other directly. High nitrates can inhibit calcium uptake by your coralline algae and corals as can low pH. High levels of calcium can cause calcium precipitation (calcium “rain”) which can coat everything in your aquarium and make a huge mess all over your rock and corals. Remember to test, test, and test again! Don’t fall into the trap of thinking that your aquarium has been doing well for so long that you don’t really need to test anymore becomes your motto. I’ve seen many an aquarium-keeper cry because he did not nip a problem in the bud by keeping on top of his/her testing.
The “Pungent” Algae
I have no doubt that MANY, MANY of you have experienced the no. 1 scourge of the home aquarium – Hair Algae! They are hardy and resilient and pretty blasted frustrating! Even with 16+ years of experience, I too still run into an unruly clump or two every once in a blue moon.
Typically called “hair” algae because of its physical appearance, it is easily identifiable as it grows in fuzzy dark green hard to remove tufts (Bryopsis has a bit more form looking similar to a fern or feather) and found to manifest itself for no apparent reason. These tufts eventually expand and will envelope all available rock and corals if left unchecked. In addition to its appearance it has a somewhat undesirable smell and probably tastes just as good which is why no self-respecting fish will eat it. Some claim that species of the rabbitfish family, algae eating blennies (Lawnmover and Bi-color), or particular tangs such as the Naso Tang (and others from the Zebrasoma and Ctenochaetus families) may help keep small amounts culled. Other animals such as the Emerald crab (Mithrax spp.), Longspine urchin (Diadema spp.), Lettuce Sea Slug (Tridachia crispa) have been known to do well against various hair algae. However, if the outbreak is massive these animal remedies will not prevent the algae from spreading unless you understand what is causing it.
Its sudden appearance is theorized to come from either waste from newly acquired animals carrying the algae in their gut, or frozen food that may be carrying fragments, or more likely culprit, water in which newly acquired fish have been transported. It is very difficult to avoid the eventual contraction of an algae species unless one is very careful with acclimation of new animals. In some cases, a two week quarantine will ensure that new animals will have a chance to empty their gut of all possible algae fragments.
Species such as Bryopsis are especially difficult to remove once it is rooted and is one of the telling characteristics of this type of algae. Means of ridding your aquarium of it start with testing your water and keeping your water parameters under control (See corresponding article on water testing). Installing a dependable protein skimmer is paramount in the fight against waste and dissolved organics in your system which can elevate your nitrates. High nitrates are fuel for the fire when it comes to algae and your nitrates need to be kept at levels of less than 5 mg/l, preferably 0 mg/l. Practicing de-sedimentation, or dislodging detritus and organics, with a basting bulb or small power-head will assist you in this by keeping gunk from settling in and under rocks. Nitrates will leach into organics that have a chance to settle and concentrate and build up over time. De-sedimentation before water changes will ensure that this does not happen and will also give your protein skimmer a chance to be more productive. Also, if you have large patches of algae, preen as much as you can out of your aquarium before you change the water. Algae stores nitrates and by removing it will help you in the fight to lower them. Last but not least, water changes! If you find that you have high nitrates then you may have no other alternative than to change out large portions of your aquarium water. Never change more than 50% of your aquarium water as 10-15% of your beneficial bacteria live in it. If you have a freshwater aquarium, gravel-vac 50% of your gravel while changing the water. Do not gravel-vac the other half until 2 weeks have passed. You may change another 50% of the water after a couple of days.
One quick note, make sure you are not OVERFEEDING! By-far the most overlooked reason for high nitrates!
If you still can’t seem to get it under control consider trying a Sea Hare.
In the very near future we will be testing a new product for eradicating hair algae and will relay our findings once we’ve finished our trials. However, even if it is found to be helpful everyone needs to remember that any kind of treatment is only a band-aid and not the remedy. If you have an outbreak of any kind of algae, dinoflagellate, or cyanobacterium, testing will give you a profile of your aquarium and possibly the reason for whatever outbreak you’re experiencing at which point you can diagnose and take appropriate action.