While there are many different compounds in chemistry with the word acid in their name, what we are talking about here are 2 major types of acids.
These major types are commonly referred to as either mineral acids and organic acids.
Mineral acids are water soluble and formed from reactions of inorganic minerals. Inorganic meaning does not contain carbon.
Organic acids may be either water soluble or water insoluble (i.e. oil soluble) and do contain carbon. Their properties and solubility depend on their structure, which we won't go into here.
Compounds containing carbon are what make up the field of organic chemistry, hence the term organic acids.
Muratic acid is a type of mineral acid, which is actually dilute hydrochloric acid, typically about 31.5%. This is also what your stomach acid is made of.
Mineral acids are typically MUCH stronger than organic acids. While we may think that's great, there are consequences that come with that. Commercial muratic also likely contains metals.
Mineral acids are also MUCH more hazardous to handle! We typically don't need that kind of strength in an acid for our use.
I would caution anyone thinking about using a mineral acid to get well trained and equipped with appropriate Personal Protection Equipment 'PPE' (gloves, goggles and possibly a respirator).
Also consider how you are going to dispose of the mineral acid after use. It may be illegal to pour it into a street sewer, stream, lake, etc. and will likely kill your lawn.
Two organic acids we are familiar with are vinegar (aka~ 5% acetic acid) and citric acid.
Vinegar, while available and cheap has one slight potential issue. Some adhesives have compounds like ethyl acetate in them, which is susceptible to vinegar causing it to soften.
Many of us have read about Vortech power head wet sides in particular losing integrity over time when cleaned in vinegar.
Citric acid does not produce that result and also has a major advantage in reef keeping. It has a high propensity to dissolve phosphate and calcium phosphate. It is also much safer than muratic.
My first choice for cleaning reef gear is citric acid. Before using previously used reef rock, I suggest soaking it in a 3% solution for several hours then rinsing well. You can dilute the leftover liquid 10:1 with water after use, and spread it on your lawn.
Reef rock will naturally form a layer of calcium phosphate in a reef system over time. You can't prevent it. It is a thermodynamically dependent reaction.
The citric acid bath will help dissolve that calcium phosphate layer and 'renew' the rock, minimizing or eliminating phosphate from leaching into the tank water, at least for a few years.
When using acids and diluting them, the percentage is always calculated based on mass (grams), So 5% citric acid solution is made of 5 grams citric acid added to 95 grams of pure water.
When diluting acids ALWAYS add the acid gradually to the water, while gently stirring.
If diluting strong mineral acids the reaction with water can be highly exothermic and generate tremendous heat! This reaction is usually conducted in a laboratory setting, by trained individuals using an ice bath to minimize the heat evolved. Done quickly can result in boiling acid being sprayed into the air, or your face! Ask me how I know? (high school chemistry teacher accident).
Good luck & be careful!
Not the best or safest way to use but there ya are.
